The patch titled
Subject: ptrace/x86: simplify the "disable" logic in ptrace_write_dr7()
has been added to the -mm tree. Its filename is
ptrace-x86-simplify-the-disable-logic-in-ptrace_write_dr7.patch
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: ptrace/x86: simplify the "disable" logic in ptrace_write_dr7()
ptrace_write_dr7() looks unnecessarily overcomplicated. We can factor out
ptrace_modify_breakpoint() and do not do "continue" twice, just we need to
pass the proper "disabled" argument to ptrace_modify_breakpoint().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
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 | 38 +++++++++++++------------------------
1 file changed, 14 insertions(+), 24 deletions(-)
diff -puN arch/x86/kernel/ptrace.c~ptrace-x86-simplify-the-disable-logic-in-ptrace_write_dr7 arch/x86/kernel/ptrace.c
--- a/arch/x86/kernel/ptrace.c~ptrace-x86-simplify-the-disable-logic-in-ptrace_write_dr7
+++ a/arch/x86/kernel/ptrace.c
@@ -637,9 +637,7 @@ static int ptrace_write_dr7(struct task_
struct thread_struct *thread = &(tsk->thread);
unsigned long old_dr7;
int i, orig_ret = 0, rc = 0;
- int enabled, second_pass = 0;
- unsigned len, type;
- struct perf_event *bp;
+ int second_pass = 0;
data &= ~DR_CONTROL_RESERVED;
old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
@@ -649,30 +647,22 @@ restore:
* appropriate changes to each.
*/
for (i = 0; i < HBP_NUM; i++) {
- enabled = decode_dr7(data, i, &len, &type);
- bp = thread->ptrace_bps[i];
+ unsigned len, type;
+ bool disabled = !decode_dr7(data, i, &len, &type);
+ struct perf_event *bp = thread->ptrace_bps[i];
- if (!enabled) {
- if (bp) {
- /*
- * Don't unregister the breakpoints right-away,
- * unless all register_user_hw_breakpoint()
- * requests have succeeded. This prevents
- * any window of opportunity for debug
- * register grabbing by other users.
- */
- if (!second_pass)
- continue;
-
- rc = ptrace_modify_breakpoint(bp, len, type,
- tsk, 1);
- if (rc)
- break;
- }
- continue;
+ if (disabled) {
+ /*
+ * Don't unregister the breakpoints right-away, unless
+ * all register_user_hw_breakpoint() requests have
+ * succeeded. This prevents any window of opportunity
+ * for debug register grabbing by other users.
+ */
+ if (!bp || !second_pass)
+ continue;
}
- rc = ptrace_modify_breakpoint(bp, len, type, tsk, 0);
+ rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled);
if (rc)
break;
}
_
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
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