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author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2007-03-05 23:35:38 +0100 |
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committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2007-03-05 23:35:38 +0100 |
commit | f794c8279d02ccd69429d816eb03fa12c130d06d (patch) | |
tree | e062a37c5dfa908599b98724778bb78228a85abf /arch/s390/kernel | |
parent | c3442e296517aee733d62fc3fe03211598902c7d (diff) | |
download | op-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>
Diffstat (limited to 'arch/s390/kernel')
-rw-r--r-- | 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); |