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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2011-04-08 17:29:36 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2011-04-25 17:36:12 +0200 |
| commit | e0ac8457d020c0289ea566917267da9e5e6d9865 (patch) | |
| tree | 85c7ad75fc186feceffac2de16b5a195d0cae8af | |
| parent | bf0b8f4b55e591ba417c2dbaff42769e1fc773b0 (diff) | |
| download | blackbird-op-linux-e0ac8457d020c0289ea566917267da9e5e6d9865.tar.gz blackbird-op-linux-e0ac8457d020c0289ea566917267da9e5e6d9865.zip | |
sh, hw_breakpoints: Fix racy access to ptrace breakpoints
While the tracer accesses ptrace breakpoints, the child task may
concurrently exit due to a SIGKILL and thus release its breakpoints
at the same time. We can then dereference some freed pointers.
To fix this, hold a reference on the child breakpoints before
manipulating them.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1302284067-7860-6-git-send-email-fweisbec@gmail.com
| -rw-r--r-- | arch/sh/kernel/ptrace_32.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/sh/kernel/ptrace_32.c b/arch/sh/kernel/ptrace_32.c index 2130ca674e9b..3d7b209b2178 100644 --- a/arch/sh/kernel/ptrace_32.c +++ b/arch/sh/kernel/ptrace_32.c @@ -117,7 +117,11 @@ void user_enable_single_step(struct task_struct *child) set_tsk_thread_flag(child, TIF_SINGLESTEP); + if (ptrace_get_breakpoints(child) < 0) + return; + set_single_step(child, pc); + ptrace_put_breakpoints(child); } void user_disable_single_step(struct task_struct *child) |
