diff options
| author | Frederic Weisbecker <[email protected]> | 2011-04-08 17:29:36 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <[email protected]> | 2011-04-25 17:33:54 +0200 |
| commit | 07fa7a0a8a586c01a8b416358c7012dcb9dc688d (patch) | |
| tree | 2200131ce41d391b0733fdd5c4c8abeaddceca78 | |
| parent | 87dc669ba25777b67796d7262c569429e58b1ed4 (diff) | |
powerpc, 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 <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Acked-by: Prasad <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: v2.6.33.. <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
| -rw-r--r-- | arch/powerpc/kernel/ptrace.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index 55613e33e263..4edeeb325429 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -1591,7 +1591,10 @@ long arch_ptrace(struct task_struct *child, long request, } case PTRACE_SET_DEBUGREG: + if (ptrace_get_breakpoints(child) < 0) + return -ESRCH; ret = ptrace_set_debugreg(child, addr, data); + ptrace_put_breakpoints(child); break; #ifdef CONFIG_PPC64 |