The patch titled Subject: ptrace/x86: revert "hw_breakpoints: Fix racy access to ptrace breakpoints" has been added to the -mm tree. Its filename is ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Oleg Nesterov <oleg@xxxxxxxxxx> Subject: ptrace/x86: revert "hw_breakpoints: Fix racy access to ptrace breakpoints" This reverts commit 87dc669ba257 ("hw_breakpoints: Fix racy access to ptrace breakpoints"). The patch was fine but we can no longer race with SIGKILL after 9899d11f ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL"), the __TASK_TRACED tracee can't be woken up and ->ptrace_bps[] can't go away. The patch only removes ptrace_get_breakpoints/ptrace_put_breakpoints and does a couple of "while at it" cleanups, it doesn't remove other changes from the reverted commit. Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Acked-by: Ingo Molnar <mingo@xxxxxxxxxx> Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx> Cc: Michael Neuling <mikey@xxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Paul Mundt <lethal@xxxxxxxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: Prasad <prasad@xxxxxxxxxxxxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/ptrace.c | 28 +++++----------------------- 1 file changed, 5 insertions(+), 23 deletions(-) diff -puN arch/x86/kernel/ptrace.c~ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints arch/x86/kernel/ptrace.c --- a/arch/x86/kernel/ptrace.c~ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints +++ a/arch/x86/kernel/ptrace.c @@ -641,9 +641,6 @@ static int ptrace_write_dr7(struct task_ unsigned len, type; struct perf_event *bp; - if (ptrace_get_breakpoints(tsk) < 0) - return -ESRCH; - data &= ~DR_CONTROL_RESERVED; old_dr7 = ptrace_get_dr7(thread->ptrace_bps); restore: @@ -692,9 +689,7 @@ restore: goto restore; } - ptrace_put_breakpoints(tsk); - - return ((orig_ret < 0) ? orig_ret : rc); + return orig_ret < 0 ? orig_ret : rc; } /* @@ -706,18 +701,10 @@ static unsigned long ptrace_get_debugreg unsigned long val = 0; if (n < HBP_NUM) { - struct perf_event *bp; - - if (ptrace_get_breakpoints(tsk) < 0) - return -ESRCH; + struct perf_event *bp = thread->ptrace_bps[n]; - bp = thread->ptrace_bps[n]; - if (!bp) - val = 0; - else + if (bp) val = bp->hw.info.address; - - ptrace_put_breakpoints(tsk); } else if (n == 6) { val = thread->debugreg6; } else if (n == 7) { @@ -734,9 +721,6 @@ static int ptrace_set_breakpoint_addr(st struct perf_event_attr attr; int err = 0; - if (ptrace_get_breakpoints(tsk) < 0) - return -ESRCH; - if (!t->ptrace_bps[nr]) { ptrace_breakpoint_init(&attr); /* @@ -762,7 +746,7 @@ static int ptrace_set_breakpoint_addr(st */ if (IS_ERR(bp)) { err = PTR_ERR(bp); - goto put; + goto out; } t->ptrace_bps[nr] = bp; @@ -773,9 +757,7 @@ static int ptrace_set_breakpoint_addr(st attr.bp_addr = addr; err = modify_user_hw_breakpoint(bp, &attr); } - -put: - ptrace_put_breakpoints(tsk); +out: return err; } _ Patches currently in -mm which might be from oleg@xxxxxxxxxx are posix_cpu_timer-consolidate-expiry-time-type.patch posix_cpu_timers-consolidate-timer-list-cleanups.patch posix_cpu_timers-consolidate-expired-timers-check.patch posix-timers-correctly-get-dying-task-time-sample-in-posix_cpu_timer_schedule.patch posix_timers-fix-racy-timer-delta-caching-on-task-exit.patch lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch ptrace-powerpc-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch ptrace-arm-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch ptrace-sh-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch ptrace-revert-prepare-to-fix-racy-accesses-on-task-breakpoints.patch ptrace-x86-simplify-the-disable-logic-in-ptrace_write_dr7.patch ptrace-x86-dont-delay-disable-till-second-pass-in-ptrace_write_dr7.patch ptrace-x86-introduce-ptrace_register_breakpoint.patch ptrace-x86-ptrace_write_dr7-should-create-bp-if-disabled.patch ptrace-x86-cleanup-ptrace_set_debugreg.patch ptrace-ptrace_detach-should-do-flush_ptrace_hw_breakpointchild.patch ptrace-x86-flush_ptrace_hw_breakpoint-shoule-clear-the-virtual-debug-registers.patch x86-kill-tif_debug.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html