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| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-03 20:20:10 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2014-04-17 21:58:20 +0200 |
| commit | 014940bad8e46ca7bd0483f760f9cba60088a3d4 (patch) | |
| tree | cbefdeb0f0d2b84f7609313f28fdf460c42dfaac /kernel/events/uprobes.c | |
| parent | e55848a4f8ee52465771983e144f0c3337776eda (diff) | |
| download | lwn-014940bad8e46ca7bd0483f760f9cba60088a3d4.tar.gz lwn-014940bad8e46ca7bd0483f760f9cba60088a3d4.zip | |
uprobes/x86: Send SIGILL if arch_uprobe_post_xol() fails
Currently the error from arch_uprobe_post_xol() is silently ignored.
This doesn't look good and this can lead to the hard-to-debug problems.
1. Change handle_singlestep() to loudly complain and send SIGILL.
Note: this only affects x86, ppc/arm can't fail.
2. Change arch_uprobe_post_xol() to call arch_uprobe_abort_xol() and
avoid TF games if it is going to return an error.
This can help to to analyze the problem, if nothing else we should
not report ->ip = xol_slot in the core-file.
Note: this means that handle_riprel_post_xol() can be called twice,
but this is fine because it is idempotent.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
Diffstat (limited to 'kernel/events/uprobes.c')
| -rw-r--r-- | kernel/events/uprobes.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index ea2a7c0728bb..d1edc5e6fd03 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1867,10 +1867,11 @@ out: static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) { struct uprobe *uprobe; + int err = 0; uprobe = utask->active_uprobe; if (utask->state == UTASK_SSTEP_ACK) - arch_uprobe_post_xol(&uprobe->arch, regs); + err = arch_uprobe_post_xol(&uprobe->arch, regs); else if (utask->state == UTASK_SSTEP_TRAPPED) arch_uprobe_abort_xol(&uprobe->arch, regs); else @@ -1884,6 +1885,11 @@ static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) spin_lock_irq(¤t->sighand->siglock); recalc_sigpending(); /* see uprobe_deny_signal() */ spin_unlock_irq(¤t->sighand->siglock); + + if (unlikely(err)) { + uprobe_warn(current, "execute the probed insn, sending SIGILL."); + force_sig_info(SIGILL, SEND_SIG_FORCED, current); + } } /* |