path: root/arch
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authorFrederic Weisbecker <fweisbec@gmail.com>2011-04-07 16:53:20 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-05-21 15:13:05 -0700
commitf372134eed7fd6ab754cbb1e671fc39fd5dd16b6 (patch)
tree32ab570a1b8ad0156940714e2da34c7f8c3af6c4 /arch
parentecff5f1a67ee54409b65a7621ba0c5709f2b79b7 (diff)
ptrace: Prepare to fix racy accesses on task breakpoints
commit bf26c018490c2fce7fe9b629083b96ce0e6ad019 upstream. When a task is traced and is in a stopped state, the tracer may execute a ptrace request to examine the tracee state and get its task struct. Right after, the tracee can be killed and thus its breakpoints released. This can happen concurrently when the tracer is in the middle of reading or modifying these breakpoints, leading to dereferencing a freed pointer. Hence, to prepare the fix, create a generic breakpoint reference holding API. When a reference on the breakpoints of a task is held, the breakpoints won't be released until the last reference is dropped. After that, no more ptrace request on the task's breakpoints can be serviced for the tracer. Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> 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> Cc: Paul Mundt <lethal@linux-sh.org> Link: http://lkml.kernel.org/r/1302284067-7860-2-git-send-email-fweisbec@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch')
0 files changed, 0 insertions, 0 deletions