Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f794c8279d02ccd69429d816eb03fa12c130d06d
Commit: f794c8279d02ccd69429d816eb03fa12c130d06d
Parent: c3442e296517aee733d62fc3fe03211598902c7d
Author: Martin Schwidefsky <[EMAIL PROTECTED]>
AuthorDate: Mon Mar 5 23:35:38 2007 +0100
Committer: Martin Schwidefsky <[EMAIL PROTECTED]>
CommitDate: Mon Mar 5 23:35:38 2007 +0100
[S390] kprobes breaks BUG_ON
The illegal operation handler calls the die notifier with DIE_BPT to
let kprobes pick up its breakpoint. If kprobes does not find its
breakpoint it returns NOTIFY_STOP instead of NOTIFY_DONE.
Since we use stop_machine_run on s390 to arm/disarm the kprobes
breakpoints the race that kprobe_handler tries to solve by checking
for the kprobes breakpoints does not exist. Removing the check makes
BUG_ON working again.
Signed-off-by: Martin Schwidefsky <[EMAIL PROTECTED]>
---
arch/s390/kernel/kprobes.c | 21 +++++++--------------
1 files changed, 7 insertions(+), 14 deletions(-)
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index a466bab..8af549e 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -337,21 +337,14 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
}
p = get_kprobe(addr);
- if (!p) {
- if (*addr != BREAKPOINT_INSTRUCTION) {
- /*
- * The breakpoint instruction was removed right
- * after we hit it. Another cpu has removed
- * either a probepoint or a debugger breakpoint
- * at this address. In either case, no further
- * handling of this interrupt is appropriate.
- *
- */
- ret = 1;
- }
- /* Not one of ours: let kernel handle it */
+ if (!p)
+ /*
+ * No kprobe at this address. The fault has not been
+ * caused by a kprobe breakpoint. The race of breakpoint
+ * vs. kprobe remove does not exist because on s390 we
+ * use stop_machine_run to arm/disarm the breakpoints.
+ */
goto no_kprobe;
- }
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
set_current_kprobe(p, regs, kcb);
-
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