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authorOleg Nesterov <oleg@redhat.com>2014-04-03 20:20:10 +0200
committerOleg Nesterov <oleg@redhat.com>2014-04-17 21:58:20 +0200
commit014940bad8e46ca7bd0483f760f9cba60088a3d4 (patch)
treecbefdeb0f0d2b84f7609313f28fdf460c42dfaac /kernel/events
parente55848a4f8ee52465771983e144f0c3337776eda (diff)
downloadblackbird-op-linux-014940bad8e46ca7bd0483f760f9cba60088a3d4.tar.gz
blackbird-op-linux-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')
-rw-r--r--kernel/events/uprobes.c8
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(&current->sighand->siglock);
recalc_sigpending(); /* see uprobe_deny_signal() */
spin_unlock_irq(&current->sighand->siglock);
+
+ if (unlikely(err)) {
+ uprobe_warn(current, "execute the probed insn, sending SIGILL.");
+ force_sig_info(SIGILL, SEND_SIG_FORCED, current);
+ }
}
/*
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