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With commit 49dca5aebfdeadd4bf27b6cb4c60392147dc35a4 I introduced
a bug (visible if CONFIG_PROVE_RCU is enabled) which occures when a panic
has happened:
[ 1526.520230] ===============================
[ 1526.520230] [ INFO: suspicious RCU usage. ]
[ 1526.520230] 3.5.0-rc1+ #12 Not tainted
[ 1526.520230] -------------------------------
[ 1526.520230] /c/kernel-tests/mm/include/linux/rcupdate.h:436 Illegal context switch in RCU read-side critical section!
[ 1526.520230]
[ 1526.520230] other info that might help us debug this:
[ 1526.520230]
[ 1526.520230]
[ 1526.520230] rcu_scheduler_active = 1, debug_locks = 0
[ 1526.520230] 3 locks held by net.agent/3279:
[ 1526.520230] #0: (&mm->mmap_sem){++++++}, at: [<ffffffff82f85962>] do_page_fault+0x193/0x390
[ 1526.520230] #1: (panic_lock){+.+...}, at: [<ffffffff82ed2830>] panic+0x37/0x1d3
[ 1526.520230] #2: (rcu_read_lock){.+.+..}, at: [<ffffffff810b9b28>] rcu_lock_acquire+0x0/0x29
[ 1526.520230]
[ 1526.520230] stack backtrace:
[ 1526.520230] Pid: 3279, comm: net.agent Not tainted 3.5.0-rc1+ #12
[ 1526.520230] Call Trace:
[ 1526.520230] [<ffffffff810e1570>] lockdep_rcu_suspicious+0x109/0x112
[ 1526.520230] [<ffffffff810bfe3a>] rcu_preempt_sleep_check+0x45/0x47
[ 1526.520230] [<ffffffff810bfe5a>] __might_sleep+0x1e/0x19a
[ 1526.520230] [<ffffffff82f8010e>] down_write+0x26/0x81
[ 1526.520230] [<ffffffff8276a966>] led_trigger_unregister+0x1f/0x9c
[ 1526.520230] [<ffffffff8276def5>] heartbeat_reboot_notifier+0x15/0x19
[ 1526.520230] [<ffffffff82f85bf5>] notifier_call_chain+0x96/0xcd
[ 1526.520230] [<ffffffff82f85cba>] __atomic_notifier_call_chain+0x8e/0xff
[ 1526.520230] [<ffffffff81094b7c>] ? kmsg_dump+0x37/0x1eb
[ 1526.520230] [<ffffffff82f85d3f>] atomic_notifier_call_chain+0x14/0x16
[ 1526.520230] [<ffffffff82ed28e1>] panic+0xe8/0x1d3
[ 1526.520230] [<ffffffff811473e2>] out_of_memory+0x15d/0x1d3
So in case of a panic, now just turn of the LED. Other approaches like
scheduling a work to unregister the trigger aren't working because there
isn't much which still runs after a panic occured (except timers).
Signed-off-by: Alexander Holler <holler@ahsoftware.de>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
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A halted kernel should not show a heartbeat.
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Alexander Holler <holler@ahsoftware.de>
Cc: Shuah Khan <shuahkhan@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Bryan Wu <bryan.wu@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Change existing triggers backlight, gpio, and heartbeat to use the new
->activated flag to set activate successful status in their activate
routines and check it in their deactivate routines to do cleanup.
Signed-off-by: Shuah Khan <shuahkhan@gmail.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Bryan Wu <bryan.wu@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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This patch allows drivers to override the default maximum brightness value
of 255. We take care to preserve backwards-compatibility as much as
possible, so that user-space ABI doesn't change for existing drivers.
LED trigger code has also been updated to use the per-LED maximum.
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
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Add an LED trigger acts like a heart beat. This can be used as a
replacement of CONFIG_HEARTBEAT code exists in some arch's timer code.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Richard Purdie <rpurdie@rpsys.net>
Cc: "Nish Aravamudan" <nish.aravamudan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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