| commit | 5be71b61f17b0e3bc8ad0b1a1b7b53ab7d574ebb | |
| author | Frederic Weisbecker <fweisbec@gmail.com> | |
| Sun, 15 Mar 2009 21:10:37 +0000 (15 22:10 +0100) | ||
| committer | Ingo Molnar <mingo@elte.hu> | |
| Mon, 16 Mar 2009 08:13:16 +0000 (16 09:13 +0100) | ||
| tree | 7ab4c915871b464a08de974570900381b169e034 | treesnapshot (tar.gz zip) |
| parent | 6404434525bb9f8f2239998f30fd7c93f2efa5b3 | commitdiff |
tracing/syscalls: protect thread flag toggling from races
Impact: fix syscall tracer enable/disable race
The current thread flag toggling is racy as shown in the following
scenario:
- task A is the last user of syscall tracing, it releases the
TIF_SYSCALL_FTRACE on each tasks
- at the same time task B start syscall tracing. refcount == 0 so
it sets up TIF_SYSCALL_FTRACE on each tasks.
The effect of the mixup is unpredictable.
So this fix adds a mutex on {start,stop}_syscall_tracing().
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <1237151439-6755-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix syscall tracer enable/disable race
The current thread flag toggling is racy as shown in the following
scenario:
- task A is the last user of syscall tracing, it releases the
TIF_SYSCALL_FTRACE on each tasks
- at the same time task B start syscall tracing. refcount == 0 so
it sets up TIF_SYSCALL_FTRACE on each tasks.
The effect of the mixup is unpredictable.
So this fix adds a mutex on {start,stop}_syscall_tracing().
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <1237151439-6755-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| kernel/trace/trace_syscalls.c | diffblobblamehistory |