| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 09/73] uprobes, x86: Fix _TIF_UPROBE vs _TIF_NOTIFY_RESUME | Date | Fri, 5 Dec 2014 14:44:15 -0800 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Andy Lutomirski <luto@amacapital.net>
commit 82975bc6a6df743b9a01810fb32cb65d0ec5d60b upstream.
x86 call do_notify_resume on paranoid returns if TIF_UPROBE is set but not on non-paranoid returns. I suspect that this is a mistake and that the code only works because int3 is paranoid.
Setting _TIF_NOTIFY_RESUME in the uprobe code was probably a workaround for the x86 bug. With that bug fixed, we can remove _TIF_NOTIFY_RESUME from the uprobes code.
Reported-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Borislav Petkov <bp@suse.de> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/x86/include/asm/thread_info.h | 2 +- kernel/events/uprobes.c | 1 - 2 files changed, 1 insertion(+), 2 deletions(-)
--- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -144,7 +144,7 @@ struct thread_info { /* Only used for 64 bit */ #define _TIF_DO_NOTIFY_MASK \ (_TIF_SIGPENDING | _TIF_MCE_NOTIFY | _TIF_NOTIFY_RESUME | \ - _TIF_USER_RETURN_NOTIFY) + _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE) /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW \ --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1621,7 +1621,6 @@ bool uprobe_deny_signal(void) if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) { utask->state = UTASK_SSTEP_TRAPPED; set_tsk_thread_flag(t, TIF_UPROBE); - set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); } }
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