Commit-ID: e0ac8457d020c0289ea566917267da9e5e6d9865 Gitweb: http://git.kernel.org/tip/e0ac8457d020c0289ea566917267da9e5e6d9865 Author: Frederic Weisbecker <fweisbec@xxxxxxxxx> AuthorDate: Fri, 8 Apr 2011 17:29:36 +0200 Committer: Frederic Weisbecker <fweisbec@xxxxxxxxx> CommitDate: Mon, 25 Apr 2011 17:36:12 +0200 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@xxxxxxxxxx> Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx> Acked-by: Paul Mundt <lethal@xxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: Prasad <prasad@xxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1302284067-7860-6-git-send-email-fweisbec@xxxxxxxxx --- 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 2130ca6..3d7b209 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) -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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