diff options
| 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 /arch/x86/kernel/uprobes.c | |
| parent | e55848a4f8ee52465771983e144f0c3337776eda (diff) | |
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 'arch/x86/kernel/uprobes.c')
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 08cdb82815fe..e72903eacd43 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -594,6 +594,15 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) struct uprobe_task *utask = current->utask; WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR); + + if (auprobe->ops->post_xol) { + int err = auprobe->ops->post_xol(auprobe, regs); + if (err) { + arch_uprobe_abort_xol(auprobe, regs); + return err; + } + } + current->thread.trap_nr = utask->autask.saved_trap_nr; /* * arch_uprobe_pre_xol() doesn't save the state of TIF_BLOCKSTEP @@ -605,8 +614,6 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) else if (!(auprobe->fixups & UPROBE_FIX_SETF)) regs->flags &= ~X86_EFLAGS_TF; - if (auprobe->ops->post_xol) - return auprobe->ops->post_xol(auprobe, regs); return 0; } @@ -641,8 +648,9 @@ int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, /* * This function gets called when XOL instruction either gets trapped or - * the thread has a fatal signal, so reset the instruction pointer to its - * probed address. + * the thread has a fatal signal, or if arch_uprobe_post_xol() failed. + * Reset the instruction pointer to its probed address for the potential + * restart or for post mortem analysis. */ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) { |