diff options
| author | Frederic Weisbecker <fweisbec@gmail.com> | 2011-04-08 17:29:36 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2011-04-25 17:35:18 +0200 |
| commit | bf0b8f4b55e591ba417c2dbaff42769e1fc773b0 (patch) | |
| tree | 4d70fa98ef40860ff596fccb05518c1806697a39 /arch/arm/kernel/ptrace.c | |
| parent | 07fa7a0a8a586c01a8b416358c7012dcb9dc688d (diff) | |
arm, 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: Will Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Link: http://lkml.kernel.org/r/1302284067-7860-5-git-send-email-fweisbec@gmail.com
Diffstat (limited to 'arch/arm/kernel/ptrace.c')
| -rw-r--r-- | arch/arm/kernel/ptrace.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index 2bf27f364d09..8182f45ca493 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -767,12 +767,20 @@ long arch_ptrace(struct task_struct *child, long request, #ifdef CONFIG_HAVE_HW_BREAKPOINT case PTRACE_GETHBPREGS: + if (ptrace_get_breakpoints(child) < 0) + return -ESRCH; + ret = ptrace_gethbpregs(child, addr, (unsigned long __user *)data); + ptrace_put_breakpoints(child); break; case PTRACE_SETHBPREGS: + if (ptrace_get_breakpoints(child) < 0) + return -ESRCH; + ret = ptrace_sethbpregs(child, addr, (unsigned long __user *)data); + ptrace_put_breakpoints(child); break; #endif |