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2017-03-26scsi: libiscsi: add lock around task lists to fix list corruption regressionChris Leech
commit 6f8830f5bbab16e54f261de187f3df4644a5b977 upstream. There's a rather long standing regression from the commit "libiscsi: Reduce locking contention in fast path" Depending on iSCSI target behavior, it's possible to hit the case in iscsi_complete_task where the task is still on a pending list (!list_empty(&task->running)). When that happens the task is removed from the list while holding the session back_lock, but other task list modification occur under the frwd_lock. That leads to linked list corruption and eventually a panicked system. Rather than back out the session lock split entirely, in order to try and keep some of the performance gains this patch adds another lock to maintain the task lists integrity. Major enterprise supported kernels have been backing out the lock split for while now, thanks to the efforts at IBM where a lab setup has the most reliable reproducer I've seen on this issue. This patch has been tested there successfully. Signed-off-by: Chris Leech <cleech@redhat.com> Fixes: 659743b02c41 ("[SCSI] libiscsi: Reduce locking contention in fast path") Reported-by: Prashantha Subbarao <psubbara@us.ibm.com> Reviewed-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-26give up on gcc ilog2() constant optimizationsLinus Torvalds
commit 474c90156c8dcc2fa815e6716cc9394d7930cb9c upstream. gcc-7 has an "optimization" pass that completely screws up, and generates the code expansion for the (impossible) case of calling ilog2() with a zero constant, even when the code gcc compiles does not actually have a zero constant. And we try to generate a compile-time error for anybody doing ilog2() on a constant where that doesn't make sense (be it zero or negative). So now gcc7 will fail the build due to our sanity checking, because it created that constant-zero case that didn't actually exist in the source code. There's a whole long discussion on the kernel mailing about how to work around this gcc bug. The gcc people themselevs have discussed their "feature" in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72785 but it's all water under the bridge, because while it looked at one point like it would be solved by the time gcc7 was released, that was not to be. So now we have to deal with this compiler braindamage. And the only simple approach seems to be to just delete the code that tries to warn about bad uses of ilog2(). So now "ilog2()" will just return 0 not just for the value 1, but for any non-positive value too. It's not like I can recall anybody having ever actually tried to use this function on any invalid value, but maybe the sanity check just meant that such code never made it out in public. Reported-by: Laura Abbott <labbott@redhat.com> Cc: John Stultz <john.stultz@linaro.org>, Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-22Drivers: hv: ring_buffer: count on wrap around mappings in ↵Vitaly Kuznetsov
get_next_pkt_raw() (v2) [ Upstream commit fa32ff6576623616c1751562edaed8c164ca5199 ] With wrap around mappings in place we can always provide drivers with direct links to packets on the ring buffer, even when they wrap around. Do the required updates to get_next_pkt_raw()/put_pkt_raw() The first version of this commit was reverted (65a532f3d50a) to deal with cross-tree merge issues which are (hopefully) resolved now. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Tested-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-22bpf: fix state equivalenceAlexei Starovoitov
[ Upstream commit d2a4dd37f6b41fbcad76efbf63124eb3126c66fe ] Commmits 57a09bf0a416 ("bpf: Detect identical PTR_TO_MAP_VALUE_OR_NULL registers") and 484611357c19 ("bpf: allow access into map value arrays") by themselves are correct, but in combination they make state equivalence ignore 'id' field of the register state which can lead to accepting invalid program. Fixes: 57a09bf0a416 ("bpf: Detect identical PTR_TO_MAP_VALUE_OR_NULL registers") Fixes: 484611357c19 ("bpf: allow access into map value arrays") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-22bpf: Detect identical PTR_TO_MAP_VALUE_OR_NULL registersThomas Graf
[ Upstream commit 57a09bf0a416700676e77102c28f9cfcb48267e0 ] A BPF program is required to check the return register of a map_elem_lookup() call before accessing memory. The verifier keeps track of this by converting the type of the result register from PTR_TO_MAP_VALUE_OR_NULL to PTR_TO_MAP_VALUE after a conditional jump ensures safety. This check is currently exclusively performed for the result register 0. In the event the compiler reorders instructions, BPF_MOV64_REG instructions may be moved before the conditional jump which causes them to keep their type PTR_TO_MAP_VALUE_OR_NULL to which the verifier objects when the register is accessed: 0: (b7) r1 = 10 1: (7b) *(u64 *)(r10 -8) = r1 2: (bf) r2 = r10 3: (07) r2 += -8 4: (18) r1 = 0x59c00000 6: (85) call 1 7: (bf) r4 = r0 8: (15) if r0 == 0x0 goto pc+1 R0=map_value(ks=8,vs=8) R4=map_value_or_null(ks=8,vs=8) R10=fp 9: (7a) *(u64 *)(r4 +0) = 0 R4 invalid mem access 'map_value_or_null' This commit extends the verifier to keep track of all identical PTR_TO_MAP_VALUE_OR_NULL registers after a map_elem_lookup() by assigning them an ID and then marking them all when the conditional jump is observed. Signed-off-by: Thomas Graf <tgraf@suug.ch> Reviewed-by: Josef Bacik <jbacik@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-22uapi: fix linux/packet_diag.h userspace compilation errorDmitry V. Levin
[ Upstream commit 745cb7f8a5de0805cade3de3991b7a95317c7c73 ] Replace MAX_ADDR_LEN with its numeric value to fix the following linux/packet_diag.h userspace compilation error: /usr/include/linux/packet_diag.h:67:17: error: 'MAX_ADDR_LEN' undeclared here (not in a function) __u8 pdmc_addr[MAX_ADDR_LEN]; This is not the first case in the UAPI where the numeric value of MAX_ADDR_LEN is used instead of symbolic one, uapi/linux/if_link.h already does the same: $ grep MAX_ADDR_LEN include/uapi/linux/if_link.h __u8 mac[32]; /* MAX_ADDR_LEN */ There are no UAPI headers besides these two that use MAX_ADDR_LEN. Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Acked-by: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-22dccp: fix use-after-free in dccp_feat_activate_valuesEric Dumazet
[ Upstream commit 62f8f4d9066c1c6f2474845d1ca7e2891f2ae3fd ] Dmitry reported crashes in DCCP stack [1] Problem here is that when I got rid of listener spinlock, I missed the fact that DCCP stores a complex state in struct dccp_request_sock, while TCP does not. Since multiple cpus could access it at the same time, we need to add protection. [1] BUG: KASAN: use-after-free in dccp_feat_activate_values+0x967/0xab0 net/dccp/feat.c:1541 at addr ffff88003713be68 Read of size 8 by task syz-executor2/8457 CPU: 2 PID: 8457 Comm: syz-executor2 Not tainted 4.10.0-rc7+ #127 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:15 [inline] dump_stack+0x292/0x398 lib/dump_stack.c:51 kasan_object_err+0x1c/0x70 mm/kasan/report.c:162 print_address_description mm/kasan/report.c:200 [inline] kasan_report_error mm/kasan/report.c:289 [inline] kasan_report.part.1+0x20e/0x4e0 mm/kasan/report.c:311 kasan_report mm/kasan/report.c:332 [inline] __asan_report_load8_noabort+0x29/0x30 mm/kasan/report.c:332 dccp_feat_activate_values+0x967/0xab0 net/dccp/feat.c:1541 dccp_create_openreq_child+0x464/0x610 net/dccp/minisocks.c:121 dccp_v6_request_recv_sock+0x1f6/0x1960 net/dccp/ipv6.c:457 dccp_check_req+0x335/0x5a0 net/dccp/minisocks.c:186 dccp_v6_rcv+0x69e/0x1d00 net/dccp/ipv6.c:711 ip6_input_finish+0x46d/0x17a0 net/ipv6/ip6_input.c:279 NF_HOOK include/linux/netfilter.h:257 [inline] ip6_input+0xdb/0x590 net/ipv6/ip6_input.c:322 dst_input include/net/dst.h:507 [inline] ip6_rcv_finish+0x289/0x890 net/ipv6/ip6_input.c:69 NF_HOOK include/linux/netfilter.h:257 [inline] ipv6_rcv+0x12ec/0x23d0 net/ipv6/ip6_input.c:203 __netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190 __netif_receive_skb+0x2a/0x170 net/core/dev.c:4228 process_backlog+0xe5/0x6c0 net/core/dev.c:4839 napi_poll net/core/dev.c:5202 [inline] net_rx_action+0xe70/0x1900 net/core/dev.c:5267 __do_softirq+0x2fb/0xb7d kernel/softirq.c:284 do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:902 </IRQ> do_softirq.part.17+0x1e8/0x230 kernel/softirq.c:328 do_softirq kernel/softirq.c:176 [inline] __local_bh_enable_ip+0x1f2/0x200 kernel/softirq.c:181 local_bh_enable include/linux/bottom_half.h:31 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:971 [inline] ip6_finish_output2+0xbb0/0x23d0 net/ipv6/ip6_output.c:123 ip6_finish_output+0x302/0x960 net/ipv6/ip6_output.c:148 NF_HOOK_COND include/linux/netfilter.h:246 [inline] ip6_output+0x1cb/0x8d0 net/ipv6/ip6_output.c:162 ip6_xmit+0xcdf/0x20d0 include/net/dst.h:501 inet6_csk_xmit+0x320/0x5f0 net/ipv6/inet6_connection_sock.c:179 dccp_transmit_skb+0xb09/0x1120 net/dccp/output.c:141 dccp_xmit_packet+0x215/0x760 net/dccp/output.c:280 dccp_write_xmit+0x168/0x1d0 net/dccp/output.c:362 dccp_sendmsg+0x79c/0xb10 net/dccp/proto.c:796 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:744 sock_sendmsg_nosec net/socket.c:635 [inline] sock_sendmsg+0xca/0x110 net/socket.c:645 SYSC_sendto+0x660/0x810 net/socket.c:1687 SyS_sendto+0x40/0x50 net/socket.c:1655 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x4458b9 RSP: 002b:00007f8ceb77bb58 EFLAGS: 00000282 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000017 RCX: 00000000004458b9 RDX: 0000000000000023 RSI: 0000000020e60000 RDI: 0000000000000017 RBP: 00000000006e1b90 R08: 00000000200f9fe1 R09: 0000000000000020 R10: 0000000000008010 R11: 0000000000000282 R12: 00000000007080a8 R13: 0000000000000000 R14: 00007f8ceb77c9c0 R15: 00007f8ceb77c700 Object at ffff88003713be50, in cache kmalloc-64 size: 64 Allocated: PID = 8446 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:502 set_track mm/kasan/kasan.c:514 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:605 kmem_cache_alloc_trace+0x82/0x270 mm/slub.c:2738 kmalloc include/linux/slab.h:490 [inline] dccp_feat_entry_new+0x214/0x410 net/dccp/feat.c:467 dccp_feat_push_change+0x38/0x220 net/dccp/feat.c:487 __feat_register_sp+0x223/0x2f0 net/dccp/feat.c:741 dccp_feat_propagate_ccid+0x22b/0x2b0 net/dccp/feat.c:949 dccp_feat_server_ccid_dependencies+0x1b3/0x250 net/dccp/feat.c:1012 dccp_make_response+0x1f1/0xc90 net/dccp/output.c:423 dccp_v6_send_response+0x4ec/0xc20 net/dccp/ipv6.c:217 dccp_v6_conn_request+0xaba/0x11b0 net/dccp/ipv6.c:377 dccp_rcv_state_process+0x51e/0x1650 net/dccp/input.c:606 dccp_v6_do_rcv+0x213/0x350 net/dccp/ipv6.c:632 sk_backlog_rcv include/net/sock.h:893 [inline] __sk_receive_skb+0x36f/0xcc0 net/core/sock.c:479 dccp_v6_rcv+0xba5/0x1d00 net/dccp/ipv6.c:742 ip6_input_finish+0x46d/0x17a0 net/ipv6/ip6_input.c:279 NF_HOOK include/linux/netfilter.h:257 [inline] ip6_input+0xdb/0x590 net/ipv6/ip6_input.c:322 dst_input include/net/dst.h:507 [inline] ip6_rcv_finish+0x289/0x890 net/ipv6/ip6_input.c:69 NF_HOOK include/linux/netfilter.h:257 [inline] ipv6_rcv+0x12ec/0x23d0 net/ipv6/ip6_input.c:203 __netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190 __netif_receive_skb+0x2a/0x170 net/core/dev.c:4228 process_backlog+0xe5/0x6c0 net/core/dev.c:4839 napi_poll net/core/dev.c:5202 [inline] net_rx_action+0xe70/0x1900 net/core/dev.c:5267 __do_softirq+0x2fb/0xb7d kernel/softirq.c:284 Freed: PID = 15 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack+0x43/0xd0 mm/kasan/kasan.c:502 set_track mm/kasan/kasan.c:514 [inline] kasan_slab_free+0x73/0xc0 mm/kasan/kasan.c:578 slab_free_hook mm/slub.c:1355 [inline] slab_free_freelist_hook mm/slub.c:1377 [inline] slab_free mm/slub.c:2954 [inline] kfree+0xe8/0x2b0 mm/slub.c:3874 dccp_feat_entry_destructor.part.4+0x48/0x60 net/dccp/feat.c:418 dccp_feat_entry_destructor net/dccp/feat.c:416 [inline] dccp_feat_list_pop net/dccp/feat.c:541 [inline] dccp_feat_activate_values+0x57f/0xab0 net/dccp/feat.c:1543 dccp_create_openreq_child+0x464/0x610 net/dccp/minisocks.c:121 dccp_v6_request_recv_sock+0x1f6/0x1960 net/dccp/ipv6.c:457 dccp_check_req+0x335/0x5a0 net/dccp/minisocks.c:186 dccp_v6_rcv+0x69e/0x1d00 net/dccp/ipv6.c:711 ip6_input_finish+0x46d/0x17a0 net/ipv6/ip6_input.c:279 NF_HOOK include/linux/netfilter.h:257 [inline] ip6_input+0xdb/0x590 net/ipv6/ip6_input.c:322 dst_input include/net/dst.h:507 [inline] ip6_rcv_finish+0x289/0x890 net/ipv6/ip6_input.c:69 NF_HOOK include/linux/netfilter.h:257 [inline] ipv6_rcv+0x12ec/0x23d0 net/ipv6/ip6_input.c:203 __netif_receive_skb_core+0x1ae5/0x3400 net/core/dev.c:4190 __netif_receive_skb+0x2a/0x170 net/core/dev.c:4228 process_backlog+0xe5/0x6c0 net/core/dev.c:4839 napi_poll net/core/dev.c:5202 [inline] net_rx_action+0xe70/0x1900 net/core/dev.c:5267 __do_softirq+0x2fb/0xb7d kernel/softirq.c:284 Memory state around the buggy address: ffff88003713bd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88003713bd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88003713be00: fc fc fc fc fc fc fc fc fc fc fb fb fb fb fb fb ^ Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-18ucount: Remove the atomicity from ucount->countEric W. Biederman
commit 040757f738e13caaa9c5078bca79aa97e11dde88 upstream. Always increment/decrement ucount->count under the ucounts_lock. The increments are there already and moving the decrements there means the locking logic of the code is simpler. This simplification in the locking logic fixes a race between put_ucounts and get_ucounts that could result in a use-after-free because the count could go zero then be found by get_ucounts and then be freed by put_ucounts. A bug presumably this one was found by a combination of syzkaller and KASAN. JongWhan Kim reported the syzkaller failure and Dmitry Vyukov spotted the race in the code. Fixes: f6b2db1a3e8d ("userns: Make the count of user namespaces per user") Reported-by: JongHwan Kim <zzoru007@gmail.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-18tracing: Add #undef to fix compile errorRik van Riel
commit bf7165cfa23695c51998231c4efa080fe1d3548d upstream. There are several trace include files that define TRACE_INCLUDE_FILE. Include several of them in the same .c file (as I currently have in some code I am working on), and the compile will blow up with a "warning: "TRACE_INCLUDE_FILE" redefined #define TRACE_INCLUDE_FILE syscalls" Every other include file in include/trace/events/ avoids that issue by having a #undef TRACE_INCLUDE_FILE before the #define; syscalls.h should have one, too. Link: http://lkml.kernel.org/r/20160928225554.13bd7ac6@annuminas.surriel.com Fixes: b8007ef74222 ("tracing: Separate raw syscall from syscall tracer") Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-15libceph: use BUG() instead of BUG_ON(1)Arnd Bergmann
commit d24cdcd3e40a6825135498e11c20c7976b9bf545 upstream. I ran into this compile warning, which is the result of BUG_ON(1) not always leading to the compiler treating the code path as unreachable: include/linux/ceph/osdmap.h: In function 'ceph_can_shift_osds': include/linux/ceph/osdmap.h:62:1: error: control reaches end of non-void function [-Werror=return-type] Using BUG() here avoids the warning. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-15nfit, libnvdimm: fix interleave set cookie calculationDan Williams
commit 86ef58a4e35e8fa66afb5898cf6dec6a3bb29f67 upstream. The interleave-set cookie is a sum that sanity checks the composition of an interleave set has not changed from when the namespace was initially created. The checksum is calculated by sorting the DIMMs by their location in the interleave-set. The comparison for the sort must be 64-bit wide, not byte-by-byte as performed by memcmp() in the broken case. Fix the implementation to accept correct cookie values in addition to the Linux "memcmp" order cookies, but only allow correct cookies to be generated going forward. It does mean that namespaces created by third-party-tooling, or created by newer kernels with this fix, will not validate on older kernels. However, there are a couple mitigating conditions: 1/ platforms with namespace-label capable NVDIMMs are not widely available. 2/ interleave-sets with a single-dimm are by definition not affected (nothing to sort). This covers the QEMU-KVM NVDIMM emulation case. The cookie stored in the namespace label will be fixed by any write the namespace label, the most straightforward way to achieve this is to write to the "alt_name" attribute of a namespace in sysfs. Fixes: eaf961536e16 ("libnvdimm, nfit: add interleave-set state-tracking infrastructure") Reported-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com> Tested-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-15nlm: Ensure callback code also checks that the files matchTrond Myklebust
commit 251af29c320d86071664f02c76f0d063a19fefdf upstream. It is not sufficient to just check that the lock pids match when granting a callback, we also need to ensure that we're granting the callback on the right file. Reported-by: Pankaj Singh <psingh.ait@gmail.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-15target: Fix NULL dereference during LUN lookup + active I/O shutdownNicholas Bellinger
commit bd4e2d2907fa23a11d46217064ecf80470ddae10 upstream. When transport_clear_lun_ref() is shutting down a se_lun via configfs with new I/O in-flight, it's possible to trigger a NULL pointer dereference in transport_lookup_cmd_lun() due to the fact percpu_ref_get() doesn't do any __PERCPU_REF_DEAD checking before incrementing lun->lun_ref.count after lun->lun_ref has switched to atomic_t mode. This results in a NULL pointer dereference as LUN shutdown code in core_tpg_remove_lun() continues running after the existing ->release() -> core_tpg_lun_ref_release() callback completes, and clears the RCU protected se_lun->lun_se_dev pointer. During the OOPs, the state of lun->lun_ref in the process which triggered the NULL pointer dereference looks like the following on v4.1.y stable code: struct se_lun { lun_link_magic = 4294932337, lun_status = TRANSPORT_LUN_STATUS_FREE, ..... lun_se_dev = 0x0, lun_sep = 0x0, ..... lun_ref = { count = { counter = 1 }, percpu_count_ptr = 3, release = 0xffffffffa02fa1e0 <core_tpg_lun_ref_release>, confirm_switch = 0x0, force_atomic = false, rcu = { next = 0xffff88154fa1a5d0, func = 0xffffffff8137c4c0 <percpu_ref_switch_to_atomic_rcu> } } } To address this bug, use percpu_ref_tryget_live() to ensure once __PERCPU_REF_DEAD is visable on all CPUs and ->lun_ref has switched to atomic_t, all new I/Os will fail to obtain a new lun->lun_ref reference. Also use an explicit percpu_ref_kill_and_confirm() callback to block on ->lun_ref_comp to allow the first stage and associated RCU grace period to complete, and then block on ->lun_ref_shutdown waiting for the final percpu_ref_put() to drop the last reference via transport_lun_remove_cmd() before continuing with core_tpg_remove_lun() shutdown. Reported-by: Rob Millner <rlm@daterainc.com> Tested-by: Rob Millner <rlm@daterainc.com> Cc: Rob Millner <rlm@daterainc.com> Tested-by: Vaibhav Tandon <vst@datera.io> Cc: Vaibhav Tandon <vst@datera.io> Tested-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-15fs: Better permission checking for submountsEric W. Biederman
commit 93faccbbfa958a9668d3ab4e30f38dd205cee8d8 upstream. To support unprivileged users mounting filesystems two permission checks have to be performed: a test to see if the user allowed to create a mount in the mount namespace, and a test to see if the user is allowed to access the specified filesystem. The automount case is special in that mounting the original filesystem grants permission to mount the sub-filesystems, to any user who happens to stumble across the their mountpoint and satisfies the ordinary filesystem permission checks. Attempting to handle the automount case by using override_creds almost works. It preserves the idea that permission to mount the original filesystem is permission to mount the sub-filesystem. Unfortunately using override_creds messes up the filesystems ordinary permission checks. Solve this by being explicit that a mount is a submount by introducing vfs_submount, and using it where appropriate. vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let sget and friends know that a mount is a submount so they can take appropriate action. sget and sget_userns are modified to not perform any permission checks on submounts. follow_automount is modified to stop using override_creds as that has proven problemantic. do_mount is modified to always remove the new MS_SUBMOUNT flag so that we know userspace will never by able to specify it. autofs4 is modified to stop using current_real_cred that was put in there to handle the previous version of submount permission checking. cifs is modified to pass the mountpoint all of the way down to vfs_submount. debugfs is modified to pass the mountpoint all of the way down to trace_automount by adding a new parameter. To make this change easier a new typedef debugfs_automount_t is introduced to capture the type of the debugfs automount function. Fixes: 069d5ac9ae0d ("autofs: Fix automounts by using current_real_cred()->uid") Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds") Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12mtd: nand: ifc: Fix location of eccstat registers for IFC V1.0Mark Marshall
commit 656441478ed55d960df5f3ccdf5a0f8c61dfd0b3 upstream. The commit 7a654172161c ("mtd/ifc: Add support for IFC controller version 2.0") added support for version 2.0 of the IFC controller. The version 2.0 controller has the ECC status registers at a different location to the previous versions. Correct the fsl_ifc_nand structure so that the ECC status can be read from the correct location for both version 1.0 and 2.0 of the controller. Fixes: 7a654172161c ("mtd/ifc: Add support for IFC controller version 2.0") Signed-off-by: Mark Marshall <mark.marshall@omicronenergy.com> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12RDMA/core: Fix incorrect structure packing for booleansJason Gunthorpe
commit 55efcfcd7776165b294f8b5cd6e05ca00ec89b7c upstream. The RDMA core uses ib_pack() to convert from unpacked CPU structs to on-the-wire bitpacked structs. This process requires that 1 bit fields are declared as u8 in the unpacked struct, otherwise the packing process does not read the value properly and the packed result is wired to 0. Several places wrongly used int. Crucially this means the kernel has never, set reversible correctly in the path record request. It has always asked for irreversible paths even if the ULP requests otherwise. When the kernel is used with a SM that supports this feature, it completely breaks communication management if reversible paths are not properly requested. The only reason this ever worked is because opensm ignores the reversible bit. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12Drivers: hv: vmbus: Fix a rescind handling bugK. Y. Srinivasan
commit ccb61f8a99e6c29df4fb96a65dad4fad740d5be9 upstream. The host can rescind a channel that has been offered to the guest and once the channel is rescinded, the host does not respond to any requests on that channel. Deal with the case where the guest may be blocked waiting for a response from the host. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12scsi: use 'scsi_device_from_queue()' for scsi_dhHannes Reinecke
commit 857de6e00778738dc3d61f75acbac35bdc48e533 upstream. The device handler needs to check if a given queue belongs to a scsi device; only then does it make sense to attach a device handler. [mkp: dropped flags] Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12PM / devfreq: Fix available_governor sysfsChanwoo Choi
commit bcf23c79c4e46130701370af4383b61a3cba755c upstream. The devfreq using passive governor is not able to change the governor. So, the user can not change the governor through 'available_governor' sysfs entry. Also, the devfreq which don't use the passive governor is not able to change to 'passive' governor on the fly. Fixes: 996133119f57 ("PM / devfreq: Add new passive governor") Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12sigaltstack: support SS_AUTODISARM for CONFIG_COMPATStas Sergeev
commit 441398d378f29a5ad6d0fcda07918e54e4961800 upstream. Currently SS_AUTODISARM is not supported in compatibility mode, but does not return -EINVAL either. This makes dosemu built with -m32 on x86_64 to crash. Also the kernel's sigaltstack selftest fails if compiled with -m32. This patch adds the needed support. Link: http://lkml.kernel.org/r/20170205101213.8163-2-stsp@list.ru Signed-off-by: Stas Sergeev <stsp@users.sourceforge.net> Cc: Milosz Tanski <milosz@adfin.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Waiman Long <Waiman.Long@hpe.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: Wang Xiaoqiang <wangxq10@lzu.edu.cn> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12mm, vmscan: cleanup lru size claculationsMichal Hocko
commit fd538803731e50367b7c59ce4ad3454426a3d671 upstream. lruvec_lru_size returns the full size of the LRU list while we sometimes need a value reduced only to eligible zones (e.g. for lowmem requests). inactive_list_is_low is one such user. Later patches will add more of them. Add a new parameter to lruvec_lru_size and allow it filter out zones which are not eligible for the given context. Link: http://lkml.kernel.org/r/20170117103702.28542-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12iommu/vt-d: Fix some macros that are incorrectly specified in intel-iommuCQ Tang
commit aaa59306b0b7e0ca4ba92cc04c5db101cbb1c096 upstream. Some of the macros are incorrect with wrong bit-shifts resulting in picking the incorrect invalidation granularity. Incorrect Source-ID in extended devtlb invalidation caused device side errors. To: Joerg Roedel <joro@8bytes.org> To: David Woodhouse <dwmw2@infradead.org> Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Cc: CQ Tang <cq.tang@intel.com> Cc: Ashok Raj <ashok.raj@intel.com> Fixes: 2f26e0a9 ("iommu/vt-d: Add basic SVM PASID support") Signed-off-by: CQ Tang <cq.tang@intel.com> Signed-off-by: Ashok Raj <ashok.raj@intel.com> Tested-by: CQ Tang <cq.tang@intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-03-12ARM: at91: define LPDDR typesAlexandre Belloni
commit e3f0a4017c2143b4b813df6a93e8cf79e3f76936 upstream. The Atmel MPDDR controller support LPDDR2 and LPDDR3 memories, add their types. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Sebastian Reichel <sre@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-26ACPICA: Linuxize: Restore and fix Intel compiler buildLv Zheng
commit ffab9188e444854882dbc291500d576d6bad7b7b upstream. ACPICA commit b59347d0b8b676cb555fe8da5cad08fcd4eeb0d3 The following commit cleans up compiler specific inclusions: Commit: 9fa1cebdbfff3db8953cebca8ee327d75edefc40 Subject: ACPICA: OSL: Cleanup the inclusion order of the compiler-specific headers But breaks one thing due to the following old issue: Buidling Linux kernel with Intel compiler originally depends on acgcc.h not acintel.h. So after making Intel compiler build working in ACPICA upstream by correctly using acintel.h, it becomes unable to build Linux kernel using Intel compiler as there is no acintel.h in the kernel source tree. This patch releases acintel.h to Linux kernel and fixes its inclusion in acenv.h. Fixes: 9fa1cebdbfff (ACPICA: OSL: Cleanup the inclusion order of the compiler-specific headers) Link: https://github.com/acpica/acpica/commit/b59347d0 Tested-by: Stepan M Mishura <stepan.m.mishura@intel.com> Signed-off-by: Lv Zheng <lv.zheng@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-26ptr_ring: fix race conditions when resizingMichael S. Tsirkin
[ Upstream commit e71695307114335be1ed912f4a347396c2ed0e69 ] Resizing currently drops consumer lock. This can cause entries to be reordered, which isn't good in itself. More importantly, consumer can detect a false ring empty condition and block forever. Further, nesting of consumer within producer lock is problematic for tun, since it produces entries in a BH, which causes a lock order reversal: CPU0 CPU1 ---- ---- consume: lock(&(&r->consumer_lock)->rlock); resize: local_irq_disable(); lock(&(&r->producer_lock)->rlock); lock(&(&r->consumer_lock)->rlock); <Interrupt> produce: lock(&(&r->producer_lock)->rlock); To fix, nest producer lock within consumer lock during resize, and keep consumer lock during the whole swap operation. Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: stable@vger.kernel.org Cc: "David S. Miller" <davem@davemloft.net> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-23videodev2.h: go back to limited range Y'CbCr for SRGB and, ADOBERGBHans Verkuil
commit 35879ee4769099905fa3bda0b21e73d434e2df6a upstream. This reverts 'commit 7e0739cd9c40 ("[media] videodev2.h: fix sYCC/AdobeYCC default quantization range"). The problem is that many drivers can convert R'G'B' content (often from sensors) to Y'CbCr, but they all produce limited range Y'CbCr. To stay backwards compatible the default quantization range for sRGB and AdobeRGB Y'CbCr encoding should be limited range, not full range, even though the corresponding standards specify full range. Update the V4L2_MAP_QUANTIZATION_DEFAULT define accordingly and also update the documentation. Fixes: 7e0739cd9c40 ("[media] videodev2.h: fix sYCC/AdobeYCC default quantization range") Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-18tcp: don't annotate mark on control socket from tcp_v6_send_response()Pablo Neira
commit 92e55f412cffd016cc245a74278cb4d7b89bb3bc upstream. Unlike ipv4, this control socket is shared by all cpus so we cannot use it as scratchpad area to annotate the mark that we pass to ip6_xmit(). Add a new parameter to ip6_xmit() to indicate the mark. The SCTP socket family caches the flowi6 structure in the sctp_transport structure, so we cannot use to carry the mark unless we later on reset it back, which I discarded since it looks ugly to me. Fixes: bf99b4ded5f8 ("tcp: fix mark propagation with fwmark_reflect enabled") Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-18net: introduce device min_header_lenWillem de Bruijn
[ Upstream commit 217e6fa24ce28ec87fca8da93c9016cb78028612 ] The stack must not pass packets to device drivers that are shorter than the minimum link layer header length. Previously, packet sockets would drop packets smaller than or equal to dev->hard_header_len, but this has false positives. Zero length payload is used over Ethernet. Other link layer protocols support variable length headers. Support for validation of these protocols removed the min length check for all protocols. Introduce an explicit dev->min_header_len parameter and drop all packets below this value. Initially, set it to non-zero only for Ethernet and loopback. Other protocols can follow in a patch to net-next. Fixes: 9ed988cd5915 ("packet: validate variable length ll headers") Reported-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-18lwtunnel: valid encap attr check should return 0 when lwtunnel is disabledDavid Ahern
[ Upstream commit 2bd137de531367fb573d90150d1872cb2a2095f7 ] An error was reported upgrading to 4.9.8: root@Typhoon:~# ip route add default table 210 nexthop dev eth0 via 10.68.64.1 weight 1 nexthop dev eth0 via 10.68.64.2 weight 1 RTNETLINK answers: Operation not supported The problem occurs when CONFIG_LWTUNNEL is not enabled and a multipath route is submitted. The point of lwtunnel_valid_encap_type_attr is catch modules that need to be loaded before any references are taken with rntl held. With CONFIG_LWTUNNEL disabled, there will be no modules to load so the lwtunnel_valid_encap_type_attr stub should just return 0. Fixes: 9ed59592e3e3 ("lwtunnel: fix autoload of lwt modules") Reported-by: pupilla@libero.it Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-18netlabel: out of bound access in cipso_v4_validate()Eric Dumazet
[ Upstream commit d71b7896886345c53ef1d84bda2bc758554f5d61 ] syzkaller found another out of bound access in ip_options_compile(), or more exactly in cipso_v4_validate() Fixes: 20e2a8648596 ("cipso: handle CIPSO options correctly when NetLabel is disabled") Fixes: 446fda4f2682 ("[NetLabel]: CIPSOv4 engine") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Paul Moore <paul@paul-moore.com> Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-18can: Fix kernel panic at security_sock_rcv_skbEric Dumazet
[ Upstream commit f1712c73714088a7252d276a57126d56c7d37e64 ] Zhang Yanmin reported crashes [1] and provided a patch adding a synchronize_rcu() call in can_rx_unregister() The main problem seems that the sockets themselves are not RCU protected. If CAN uses RCU for delivery, then sockets should be freed only after one RCU grace period. Recent kernels could use sock_set_flag(sk, SOCK_RCU_FREE), but let's ease stable backports with the following fix instead. [1] BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff81495e25>] selinux_socket_sock_rcv_skb+0x65/0x2a0 Call Trace: <IRQ> [<ffffffff81485d8c>] security_sock_rcv_skb+0x4c/0x60 [<ffffffff81d55771>] sk_filter+0x41/0x210 [<ffffffff81d12913>] sock_queue_rcv_skb+0x53/0x3a0 [<ffffffff81f0a2b3>] raw_rcv+0x2a3/0x3c0 [<ffffffff81f06eab>] can_rcv_filter+0x12b/0x370 [<ffffffff81f07af9>] can_receive+0xd9/0x120 [<ffffffff81f07beb>] can_rcv+0xab/0x100 [<ffffffff81d362ac>] __netif_receive_skb_core+0xd8c/0x11f0 [<ffffffff81d36734>] __netif_receive_skb+0x24/0xb0 [<ffffffff81d37f67>] process_backlog+0x127/0x280 [<ffffffff81d36f7b>] net_rx_action+0x33b/0x4f0 [<ffffffff810c88d4>] __do_softirq+0x184/0x440 [<ffffffff81f9e86c>] do_softirq_own_stack+0x1c/0x30 <EOI> [<ffffffff810c76fb>] do_softirq.part.18+0x3b/0x40 [<ffffffff810c8bed>] do_softirq+0x1d/0x20 [<ffffffff81d30085>] netif_rx_ni+0xe5/0x110 [<ffffffff8199cc87>] slcan_receive_buf+0x507/0x520 [<ffffffff8167ef7c>] flush_to_ldisc+0x21c/0x230 [<ffffffff810e3baf>] process_one_work+0x24f/0x670 [<ffffffff810e44ed>] worker_thread+0x9d/0x6f0 [<ffffffff810e4450>] ? rescuer_thread+0x480/0x480 [<ffffffff810ebafc>] kthread+0x12c/0x150 [<ffffffff81f9ccef>] ret_from_fork+0x3f/0x70 Reported-by: Zhang Yanmin <yanmin.zhang@intel.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()Dexuan Cui
commit 433e19cf33d34bb6751c874a9c00980552fe508c upstream. Commit a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in hv_need_to_signal_on_read()") added the proper mb(), but removed the test "prev_write_sz < pending_sz" when making the signal decision. As a result, the guest can signal the host unnecessarily, and then the host can throttle the guest because the host thinks the guest is buggy or malicious; finally the user running stress test can perceive intermittent freeze of the guest. This patch brings back the test, and properly handles the in-place consumption APIs used by NetVSC (see get_next_pkt_raw(), put_pkt_raw() and commit_rd_index()). Fixes: a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in hv_need_to_signal_on_read()") Signed-off-by: Dexuan Cui <decui@microsoft.com> Reported-by: Rolf Neugebauer <rolf.neugebauer@docker.com> Tested-by: Rolf Neugebauer <rolf.neugebauer@docker.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14Drivers: hv: vmbus: On the read path cleanup the logic to interrupt the hostK. Y. Srinivasan
commit 3372592a140db69fd63837e81f048ab4abf8111e upstream. Signal the host when we determine the host is to be signaled - on th read path. The currrent code determines the need to signal in the ringbuffer code and actually issues the signal elsewhere. This can result in the host viewing this interrupt as spurious since the host may also poll the channel. Make the necessary adjustments. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14Drivers: hv: vmbus: On write cleanup the logic to interrupt the hostK. Y. Srinivasan
commit 1f6ee4e7d83586c8b10bd4f2f4346353d04ce884 upstream. Signal the host when we determine the host is to be signaled. The currrent code determines the need to signal in the ringbuffer code and actually issues the signal elsewhere. This can result in the host viewing this interrupt as spurious since the host may also poll the channel. Make the necessary adjustments. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14target: Fix multi-session dynamic se_node_acl double free OOPsNicholas Bellinger
commit 01d4d673558985d9a118e1e05026633c3e2ade9b upstream. This patch addresses a long-standing bug with multi-session (eg: iscsi-target + iser-target) se_node_acl dynamic free withini transport_deregister_session(). This bug is caused when a storage endpoint is configured with demo-mode (generate_node_acls = 1 + cache_dynamic_acls = 1) initiators, and initiator login creates a new dynamic node acl and attaches two sessions to it. After that, demo-mode for the storage instance is disabled via configfs (generate_node_acls = 0 + cache_dynamic_acls = 0) and the existing dynamic acl is never converted to an explicit ACL. The end result is dynamic acl resources are released twice when the sessions are shutdown in transport_deregister_session(). If the storage instance is not changed to disable demo-mode, or the dynamic acl is converted to an explict ACL, or there is only a single session associated with the dynamic ACL, the bug is not triggered. To address this big, move the release of dynamic se_node_acl memory into target_complete_nacl() so it's only freed once when se_node_acl->acl_kref reaches zero. (Drop unnecessary list_del_init usage - HCH) Reported-by: Rob Millner <rlm@daterainc.com> Tested-by: Rob Millner <rlm@daterainc.com> Cc: Rob Millner <rlm@daterainc.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-14cpumask: use nr_cpumask_bits for parsing functionsTejun Heo
commit 4d59b6ccf000862beed6fc0765d3209f98a8d8a2 upstream. Commit 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions") converted both cpumask printing and parsing functions to use nr_cpu_ids instead of nr_cpumask_bits. While this was okay for the printing functions as it just picked one of the two output formats that we were alternating between depending on a kernel config, doing the same for parsing wasn't okay. nr_cpumask_bits can be either nr_cpu_ids or NR_CPUS. We can always use nr_cpu_ids but that is a variable while NR_CPUS is a constant, so it can be more efficient to use NR_CPUS when we can get away with it. Converting the printing functions to nr_cpu_ids makes sense because it affects how the masks get presented to userspace and doesn't break anything; however, using nr_cpu_ids for parsing functions can incorrectly leave the higher bits uninitialized while reading in these masks from userland. As all testing and comparison functions use nr_cpumask_bits which can be larger than nr_cpu_ids, the parsed cpumasks can erroneously yield false negative results. This made the taskstats interface incorrectly return -EINVAL even when the inputs were correct. Fix it by restoring the parse functions to use nr_cpumask_bits instead of nr_cpu_ids. Link: http://lkml.kernel.org/r/20170206182442.GB31078@htj.duckdns.org Fixes: 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions") Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Martin Steigerwald <martin.steigerwald@teamix.de> Debugged-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-09irqdomain: Avoid activating interrupts more than onceMarc Zyngier
commit 08d85f3ea99f1eeafc4e8507936190e86a16ee8c upstream. Since commit f3b0946d629c ("genirq/msi: Make sure PCI MSIs are activated early"), we can end-up activating a PCI/MSI twice (once at allocation time, and once at startup time). This is normally of no consequences, except that there is some HW out there that may misbehave if activate is used more than once (the GICv3 ITS, for example, uses the activate callback to issue the MAPVI command, and the architecture spec says that "If there is an existing mapping for the EventID-DeviceID combination, behavior is UNPREDICTABLE"). While this could be worked around in each individual driver, it may make more sense to tackle the issue at the core level. In order to avoid getting in that situation, let's have a per-interrupt flag to remember if we have already activated that interrupt or not. Fixes: f3b0946d629c ("genirq/msi: Make sure PCI MSIs are activated early") Reported-and-tested-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Link: http://lkml.kernel.org/r/1484668848-24361-1-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-09percpu-refcount: fix reference leak during percpu-atomic transitionDouglas Miller
commit 966d2b04e070bc040319aaebfec09e0144dc3341 upstream. percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-09base/memory, hotplug: fix a kernel oops in show_valid_zones()Toshi Kani
commit a96dfddbcc04336bbed50dc2b24823e45e09e80c upstream. Reading a sysfs "memoryN/valid_zones" file leads to the following oops when the first page of a range is not backed by struct page. show_valid_zones() assumes that 'start_pfn' is always valid for page_zone(). BUG: unable to handle kernel paging request at ffffea017a000000 IP: show_valid_zones+0x6f/0x160 This issue may happen on x86-64 systems with 64GiB or more memory since their memory block size is bumped up to 2GiB. [1] An example of such systems is desribed below. 0x3240000000 is only aligned by 1GiB and this memory block starts from 0x3200000000, which is not backed by struct page. BIOS-e820: [mem 0x0000003240000000-0x000000603fffffff] usable Since test_pages_in_a_zone() already checks holes, fix this issue by extending this function to return 'valid_start' and 'valid_end' for a given range. show_valid_zones() then proceeds with the valid range. [1] 'Commit bdee237c0343 ("x86: mm: Use 2GB memory block size on large-memory x86-64 systems")' Link: http://lkml.kernel.org/r/20170127222149.30893-3-toshi.kani@hpe.com Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Zhang Zhen <zhenzhang.zhang@huawei.com> Cc: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-04lwtunnel: Fix oops on state free after encap module unloadRobert Shearman
[ Upstream commit 85c814016ce3b371016c2c054a905fa2492f5a65 ] When attempting to free lwtunnel state after the module for the encap has been unloaded an oops occurs: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: lwtstate_free+0x18/0x40 [..] task: ffff88003e372380 task.stack: ffffc900001fc000 RIP: 0010:lwtstate_free+0x18/0x40 RSP: 0018:ffff88003fd83e88 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88002bbb3380 RCX: ffff88000c91a300 [..] Call Trace: <IRQ> free_fib_info_rcu+0x195/0x1a0 ? rt_fibinfo_free+0x50/0x50 rcu_process_callbacks+0x2d3/0x850 ? rcu_process_callbacks+0x296/0x850 __do_softirq+0xe4/0x4cb irq_exit+0xb0/0xc0 smp_apic_timer_interrupt+0x3d/0x50 apic_timer_interrupt+0x93/0xa0 [..] Code: e8 6e c6 fc ff 89 d8 5b 5d c3 bb de ff ff ff eb f4 66 90 66 66 66 66 90 55 48 89 e5 53 0f b7 07 48 89 fb 48 8b 04 c5 00 81 d5 81 <48> 8b 40 08 48 85 c0 74 13 ff d0 48 8d 7b 20 be 20 00 00 00 e8 The problem is after the module for the encap can be unloaded the corresponding ops is removed and is thus NULL here. Modules implementing lwtunnel ops should not be allowed to unload while there is state alive using those ops, so grab the module reference for the ops on creating lwtunnel state and of course release the reference when freeing the state. Fixes: 1104d9ba443a ("lwtunnel: Add destroy state operation") Signed-off-by: Robert Shearman <rshearma@brocade.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-04net: Specify the owning module for lwtunnel opsRobert Shearman
[ Upstream commit 88ff7334f25909802140e690c0e16433e485b0a0 ] Modules implementing lwtunnel ops should not be allowed to unload while there is state alive using those ops, so specify the owning module for all lwtunnel ops. Signed-off-by: Robert Shearman <rshearma@brocade.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-04lwtunnel: fix autoload of lwt modulesDavid Ahern
[ Upstream commit 9ed59592e3e379b2e9557dc1d9e9ec8fcbb33f16] Trying to add an mpls encap route when the MPLS modules are not loaded hangs. For example: CONFIG_MPLS=y CONFIG_NET_MPLS_GSO=m CONFIG_MPLS_ROUTING=m CONFIG_MPLS_IPTUNNEL=m $ ip route add 10.10.10.10/32 encap mpls 100 via inet 10.100.1.2 The ip command hangs: root 880 826 0 21:25 pts/0 00:00:00 ip route add 10.10.10.10/32 encap mpls 100 via inet 10.100.1.2 $ cat /proc/880/stack [<ffffffff81065a9b>] call_usermodehelper_exec+0xd6/0x134 [<ffffffff81065efc>] __request_module+0x27b/0x30a [<ffffffff814542f6>] lwtunnel_build_state+0xe4/0x178 [<ffffffff814aa1e4>] fib_create_info+0x47f/0xdd4 [<ffffffff814ae451>] fib_table_insert+0x90/0x41f [<ffffffff814a8010>] inet_rtm_newroute+0x4b/0x52 ... modprobe is trying to load rtnl-lwt-MPLS: root 881 5 0 21:25 ? 00:00:00 /sbin/modprobe -q -- rtnl-lwt-MPLS and it hangs after loading mpls_router: $ cat /proc/881/stack [<ffffffff81441537>] rtnl_lock+0x12/0x14 [<ffffffff8142ca2a>] register_netdevice_notifier+0x16/0x179 [<ffffffffa0033025>] mpls_init+0x25/0x1000 [mpls_router] [<ffffffff81000471>] do_one_initcall+0x8e/0x13f [<ffffffff81119961>] do_init_module+0x5a/0x1e5 [<ffffffff810bd070>] load_module+0x13bd/0x17d6 ... The problem is that lwtunnel_build_state is called with rtnl lock held preventing mpls_init from registering. Given the potential references held by the time lwtunnel_build_state it can not drop the rtnl lock to the load module. So, extract the module loading code from lwtunnel_build_state into a new function to validate the encap type. The new function is called while converting the user request into a fib_config which is well before any table, device or fib entries are examined. Fixes: 745041e2aaf1 ("lwtunnel: autoload of lwt modules") Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-04virtio-net: restore VIRTIO_HDR_F_DATA_VALID on receivingJason Wang
[ Upstream commit 6391a4481ba0796805d6581e42f9f0418c099e34 ] Commit 501db511397f ("virtio: don't set VIRTIO_NET_HDR_F_DATA_VALID on xmit") in fact disables VIRTIO_HDR_F_DATA_VALID on receiving path too, fixing this by adding a hint (has_data_valid) and set it only on the receiving path. Cc: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-04virtio: don't set VIRTIO_NET_HDR_F_DATA_VALID on xmitRolf Neugebauer
[ Upstream commit 501db511397fd6efff3aa5b4e8de415b55559550 ] This patch part reverts fd2a0437dc33 and e858fae2b0b8 which introduced a subtle change in how the virtio_net flags are derived from the SKBs ip_summed field. With the above commits, the flags are set to VIRTIO_NET_HDR_F_DATA_VALID when ip_summed == CHECKSUM_UNNECESSARY, thus treating it differently to ip_summed == CHECKSUM_NONE, which should be the same. Further, the virtio spec 1.0 / CS04 explicitly says that VIRTIO_NET_HDR_F_DATA_VALID must not be set by the driver. Fixes: fd2a0437dc33 ("virtio_net: introduce virtio_net_hdr_{from,to}_skb") Fixes: e858fae2b0b8 (" virtio_net: use common code for virtio_net_hdr and skb GSO conversion") Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-04tcp: fix tcp_fastopen unaligned access complaints on sparcShannon Nelson
[ Upstream commit 003c941057eaa868ca6fedd29a274c863167230d ] Fix up a data alignment issue on sparc by swapping the order of the cookie byte array field with the length field in struct tcp_fastopen_cookie, and making it a proper union to clean up the typecasting. This addresses log complaints like these: log_unaligned: 113 callbacks suppressed Kernel unaligned access at TPC[976490] tcp_try_fastopen+0x2d0/0x360 Kernel unaligned access at TPC[9764ac] tcp_try_fastopen+0x2ec/0x360 Kernel unaligned access at TPC[9764c8] tcp_try_fastopen+0x308/0x360 Kernel unaligned access at TPC[9764e4] tcp_try_fastopen+0x324/0x360 Kernel unaligned access at TPC[976490] tcp_try_fastopen+0x2d0/0x360 Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-01memory_hotplug: make zone_can_shift() return a boolean valueYasuaki Ishimatsu
commit 8a1f780e7f28c7c1d640118242cf68d528c456cd upstream. online_{kernel|movable} is used to change the memory zone to ZONE_{NORMAL|MOVABLE} and online the memory. To check that memory zone can be changed, zone_can_shift() is used. Currently the function returns minus integer value, plus integer value and 0. When the function returns minus or plus integer value, it means that the memory zone can be changed to ZONE_{NORNAL|MOVABLE}. But when the function returns 0, there are two meanings. One of the meanings is that the memory zone does not need to be changed. For example, when memory is in ZONE_NORMAL and onlined by online_kernel the memory zone does not need to be changed. Another meaning is that the memory zone cannot be changed. When memory is in ZONE_NORMAL and onlined by online_movable, the memory zone may not be changed to ZONE_MOVALBE due to memory online limitation(see Documentation/memory-hotplug.txt). In this case, memory must not be onlined. The patch changes the return type of zone_can_shift() so that memory online operation fails when memory zone cannot be changed as follows: Before applying patch: # grep -A 35 "Node 2" /proc/zoneinfo Node 2, zone Normal <snip> node_scanned 0 spanned 8388608 present 7864320 managed 7864320 # echo online_movable > memory4097/state # grep -A 35 "Node 2" /proc/zoneinfo Node 2, zone Normal <snip> node_scanned 0 spanned 8388608 present 8388608 managed 8388608 online_movable operation succeeded. But memory is onlined as ZONE_NORMAL, not ZONE_MOVABLE. After applying patch: # grep -A 35 "Node 2" /proc/zoneinfo Node 2, zone Normal <snip> node_scanned 0 spanned 8388608 present 7864320 managed 7864320 # echo online_movable > memory4097/state bash: echo: write error: Invalid argument # grep -A 35 "Node 2" /proc/zoneinfo Node 2, zone Normal <snip> node_scanned 0 spanned 8388608 present 7864320 managed 7864320 online_movable operation failed because of failure of changing the memory zone from ZONE_NORMAL to ZONE_MOVABLE Fixes: df429ac03936 ("memory-hotplug: more general validation of zone during online") Link: http://lkml.kernel.org/r/2f9c3837-33d7-b6e5-59c0-6ca4372b2d84@gmail.com Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Reviewed-by: Reza Arbab <arbab@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-01SUNRPC: cleanup ida information when removing sunrpc moduleKinglong Mee
commit c929ea0b910355e1876c64431f3d5802f95b3d75 upstream. After removing sunrpc module, I get many kmemleak information as, unreferenced object 0xffff88003316b1e0 (size 544): comm "gssproxy", pid 2148, jiffies 4294794465 (age 4200.081s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffffb0cfb58a>] kmemleak_alloc+0x4a/0xa0 [<ffffffffb03507fe>] kmem_cache_alloc+0x15e/0x1f0 [<ffffffffb0639baa>] ida_pre_get+0xaa/0x150 [<ffffffffb0639cfd>] ida_simple_get+0xad/0x180 [<ffffffffc06054fb>] nlmsvc_lookup_host+0x4ab/0x7f0 [lockd] [<ffffffffc0605e1d>] lockd+0x4d/0x270 [lockd] [<ffffffffc06061e5>] param_set_timeout+0x55/0x100 [lockd] [<ffffffffc06cba24>] svc_defer+0x114/0x3f0 [sunrpc] [<ffffffffc06cbbe7>] svc_defer+0x2d7/0x3f0 [sunrpc] [<ffffffffc06c71da>] rpc_show_info+0x8a/0x110 [sunrpc] [<ffffffffb044a33f>] proc_reg_write+0x7f/0xc0 [<ffffffffb038e41f>] __vfs_write+0xdf/0x3c0 [<ffffffffb0390f1f>] vfs_write+0xef/0x240 [<ffffffffb0392fbd>] SyS_write+0xad/0x130 [<ffffffffb0d06c37>] entry_SYSCALL_64_fastpath+0x1a/0xa9 [<ffffffffffffffff>] 0xffffffffffffffff I found, the ida information (dynamic memory) isn't cleanup. Signed-off-by: Kinglong Mee <kinglongmee@gmail.com> Fixes: 2f048db4680a ("SUNRPC: Add an identifier for struct rpc_clnt") Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-01nfs: Don't increment lock sequence ID after NFS4ERR_MOVEDChuck Lever
commit 059aa734824165507c65fd30a55ff000afd14983 upstream. Xuan Qi reports that the Linux NFSv4 client failed to lock a file that was migrated. The steps he observed on the wire: 1. The client sent a LOCK request to the source server 2. The source server replied NFS4ERR_MOVED 3. The client switched to the destination server 4. The client sent the same LOCK request to the destination server with a bumped lock sequence ID 5. The destination server rejected the LOCK request with NFS4ERR_BAD_SEQID RFC 3530 section 8.1.5 provides a list of NFS errors which do not bump a lock sequence ID. However, RFC 3530 is now obsoleted by RFC 7530. In RFC 7530 section 9.1.7, this list has been updated by the addition of NFS4ERR_MOVED. Reported-by: Xuan Qi <xuan.qi@oracle.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-01IB/cxgb3: fix misspelling in header guardNicolas Iooss
commit b1a27eac7fefff33ccf6acc919fc0725bf9815fb upstream. Use CXGB3_... instead of CXBG3_... Fixes: a85fb3383340 ("IB/cxgb3: Move user vendor structures") Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Reviewed-by: Leon Romanovsky <leonro@mellanox.com> Acked-by: Steve Wise <swise@chelsio.com> Signed-off-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-02-01mm, page_alloc: fix check for NULL preferred_zoneVlastimil Babka
commit ea57485af8f4221312a5a95d63c382b45e7840dc upstream. Patch series "fix premature OOM regression in 4.7+ due to cpuset races". This is v2 of my attempt to fix the recent report based on LTP cpuset stress test [1]. The intention is to go to stable 4.9 LTSS with this, as triggering repeated OOMs is not nice. That's why the patches try to be not too intrusive. Unfortunately why investigating I found that modifying the testcase to use per-VMA policies instead of per-task policies will bring the OOM's back, but that seems to be much older and harder to fix problem. I have posted a RFC [2] but I believe that fixing the recent regressions has a higher priority. Longer-term we might try to think how to fix the cpuset mess in a better and less error prone way. I was for example very surprised to learn, that cpuset updates change not only task->mems_allowed, but also nodemask of mempolicies. Until now I expected the parameter to alloc_pages_nodemask() to be stable. I wonder why do we then treat cpusets specially in get_page_from_freelist() and distinguish HARDWALL etc, when there's unconditional intersection between mempolicy and cpuset. I would expect the nodemask adjustment for saving overhead in g_p_f(), but that clearly doesn't happen in the current form. So we have both crazy complexity and overhead, AFAICS. [1] https://lkml.kernel.org/r/CAFpQJXUq-JuEP=QPidy4p_=FN0rkH5Z-kfB4qBvsf6jMS87Edg@mail.gmail.com [2] https://lkml.kernel.org/r/7c459f26-13a6-a817-e508-b65b903a8378@suse.cz This patch (of 4): Since commit c33d6c06f60f ("mm, page_alloc: avoid looking up the first zone in a zonelist twice") we have a wrong check for NULL preferred_zone, which can theoretically happen due to concurrent cpuset modification. We check the zoneref pointer which is never NULL and we should check the zone pointer. Also document this in first_zones_zonelist() comment per Michal Hocko. Fixes: c33d6c06f60f ("mm, page_alloc: avoid looking up the first zone in a zonelist twice") Link: http://lkml.kernel.org/r/20170120103843.24587-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Ganapatrao Kulkarni <gpkulkarni@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>