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| author | Keshavamurthy Anil S <anil.s.keshavamurthy@intel.com> | 2006-01-11 20:17:42 (GMT) |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-12 02:42:12 (GMT) |
| commit | eb3a72921c8276bf2cd028a458bb83435f16c91c (patch) | |
| tree | 634eff43e1926bdb400d038eb08115193b6a7506 /arch/sparc64 | |
| parent | df019b1d8b893d0f0ee5a9b0f71486f0892561ae (diff) | |
| download | linux-eb3a72921c8276bf2cd028a458bb83435f16c91c.tar.xz | |
[PATCH] kprobes: fix race in recovery of reentrant probe
There is a window where a probe gets removed right after the probe is hit
on some different cpu. In this case probe handlers can't find a matching
probe instance related to break address. In this case we need to read the
original instruction at break address to see if that is not a break/int3
instruction and recover safely.
Previous code had a bug where we were not checking for the above race in
case of reentrant probes and the below patch fixes this race.
Tested on IA64, Powerpc, x86_64.
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/sparc64')
| -rw-r--r-- | arch/sparc64/kernel/kprobes.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c index ff5e9d5..b9a9ce7 100644 --- a/arch/sparc64/kernel/kprobes.c +++ b/arch/sparc64/kernel/kprobes.c @@ -135,6 +135,14 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) prepare_singlestep(p, regs, kcb); return 1; } else { + if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) { + /* The breakpoint instruction was removed by + * another cpu right after we hit, no further + * handling of this interrupt is appropriate + */ + ret = 1; + goto no_kprobe; + } p = __get_cpu_var(current_kprobe); if (p->break_handler && p->break_handler(p, regs)) goto ss_probe; |