diff options
| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-09-22 14:40:48 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-10-05 16:12:48 +1100 |
| commit | 3368f5699a9b0e281e14f9f93244da0a922f6df0 (patch) | |
| tree | 2b0100e50a156dc60e70784e85c35a6713e7be95 /arch | |
| parent | 6baea433bc84cd148af1c524389a8d756f67412e (diff) | |
| download | linux-rt-3368f5699a9b0e281e14f9f93244da0a922f6df0.tar.gz | |
powerpc/jprobes: Validate break handler invocation as being due to a jprobe_return()
Fix a circa 2005 FIXME by implementing a check to ensure that we
actually got into the jprobe break handler() due to the trap in
jprobe_return().
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/kprobes.c | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 48a81614f629..a14c61855705 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -639,24 +639,22 @@ NOKPROBE_SYMBOL(setjmp_pre_handler); void __used jprobe_return(void) { - asm volatile("trap" ::: "memory"); + asm volatile("jprobe_return_trap:\n" + "trap\n" + ::: "memory"); } NOKPROBE_SYMBOL(jprobe_return); -static void __used jprobe_return_end(void) -{ -} -NOKPROBE_SYMBOL(jprobe_return_end); - int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) { struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - /* - * FIXME - we should ideally be validating that we got here 'cos - * of the "trap" in jprobe_return() above, before restoring the - * saved regs... - */ + if (regs->nip != ppc_kallsyms_lookup_name("jprobe_return_trap")) { + pr_debug("longjmp_break_handler NIP (0x%lx) does not match jprobe_return_trap (0x%lx)\n", + regs->nip, ppc_kallsyms_lookup_name("jprobe_return_trap")); + return 0; + } + memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); /* It's OK to start function graph tracing again */ unpause_graph_tracing(); |