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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2007-03-05 23:35:38 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2007-03-05 23:35:38 +0100
commitf794c8279d02ccd69429d816eb03fa12c130d06d (patch)
treee062a37c5dfa908599b98724778bb78228a85abf
parentc3442e296517aee733d62fc3fe03211598902c7d (diff)
downloadop-kernel-dev-f794c8279d02ccd69429d816eb03fa12c130d06d.zip
op-kernel-dev-f794c8279d02ccd69429d816eb03fa12c130d06d.tar.gz
[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 <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/kernel/kprobes.c21
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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