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| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-10-23 22:07:38 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-10 13:40:43 +0100 |
| commit | 1ffabfc1d58ba586fa11cc3cde21d54afec03387 (patch) | |
| tree | e18960f2dd1016105d220e4bdd7cc2f2d4b42098 /arch | |
| parent | f8d07852819a0c2da239fca155342b4f80f4aedf (diff) | |
| download | linux-stable-1ffabfc1d58ba586fa11cc3cde21d54afec03387.tar.gz linux-stable-1ffabfc1d58ba586fa11cc3cde21d54afec03387.tar.bz2 linux-stable-1ffabfc1d58ba586fa11cc3cde21d54afec03387.zip | |
powerpc/kprobes: Disable preemption before invoking probe handler for optprobes
commit 8a2d71a3f2737e2448aa68de2b6052cb570d3d2a upstream.
Per Documentation/kprobes.txt, probe handlers need to be invoked with
preemption disabled. Update optimized_callback() to do so. Also move
get_kprobe_ctlblk() invocation post preemption disable, since it
accesses pre-cpu data.
This was not an issue so far since optprobes wasn't selected if
CONFIG_PREEMPT was enabled. Commit a30b85df7d599f ("kprobes: Use
synchronize_rcu_tasks() for optprobe with CONFIG_PREEMPT=y") changes
this.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/optprobes.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c index 91e037ab20a1..60ba7f1370a8 100644 --- a/arch/powerpc/kernel/optprobes.c +++ b/arch/powerpc/kernel/optprobes.c @@ -115,7 +115,6 @@ static unsigned long can_optimize(struct kprobe *p) static void optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs) { - struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); unsigned long flags; /* This is possible if op is under delayed unoptimizing */ @@ -124,13 +123,14 @@ static void optimized_callback(struct optimized_kprobe *op, local_irq_save(flags); hard_irq_disable(); + preempt_disable(); if (kprobe_running()) { kprobes_inc_nmissed_count(&op->kp); } else { __this_cpu_write(current_kprobe, &op->kp); regs->nip = (unsigned long)op->kp.addr; - kcb->kprobe_status = KPROBE_HIT_ACTIVE; + get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; opt_pre_handler(&op->kp, regs); __this_cpu_write(current_kprobe, NULL); } @@ -140,6 +140,7 @@ static void optimized_callback(struct optimized_kprobe *op, * local_irq_restore() will re-enable interrupts, * if they were hard disabled. */ + preempt_enable_no_resched(); local_irq_restore(flags); } NOKPROBE_SYMBOL(optimized_callback); |