| Message ID | 162399993125.506599.11062077324255866677.stgit@devnote2 (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | kprobes: Fix stacktrace with kretprobes on x86 | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
* Masami Hiramatsu <mhiramat@kernel.org> wrote: > Commit e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler") > missed to pass the wrong trampoline address (it passes the descriptor address > instead of function entry address). > This fixes it to pass correct trampoline address to __kretprobe_trampoline_handler(). > This also changes to use correct symbol dereference function to get the > function address from the kretprobe_trampoline. > > Fixes: e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler") > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> A better changelog: The following commit: Commit e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler") Passed the wrong trampoline address to __kretprobe_trampoline_handler(): it passes the descriptor address instead of function entry address. Pass the right parameter. Also use correct symbol dereference function to get the function address from 'kretprobe_trampoline' - an IA64 special. (Although I realize that much of this goes away just a couple of patches later.) Thanks, Ingo
On Mon, 5 Jul 2021 09:46:33 +0200 Ingo Molnar <mingo@kernel.org> wrote: > > * Masami Hiramatsu <mhiramat@kernel.org> wrote: > > > Commit e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler") > > missed to pass the wrong trampoline address (it passes the descriptor address > > instead of function entry address). > > This fixes it to pass correct trampoline address to __kretprobe_trampoline_handler(). > > This also changes to use correct symbol dereference function to get the > > function address from the kretprobe_trampoline. > > > > Fixes: e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler") > > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > > A better changelog: > > The following commit: > > Commit e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler") > > Passed the wrong trampoline address to __kretprobe_trampoline_handler(): it > passes the descriptor address instead of function entry address. > > Pass the right parameter. > > Also use correct symbol dereference function to get the function address > from 'kretprobe_trampoline' - an IA64 special. Thanks for rewriting! OK, I'll update it. > > (Although I realize that much of this goes away just a couple of patches > later.) Yes, but since this is a real bug. I think I should split it for backporting to stable trees. (Oh, I also forgot to add Cc: stable. Sorry about that.) Thank you,
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c index 441ed04b1037..d4048518a1d7 100644 --- a/arch/ia64/kernel/kprobes.c +++ b/arch/ia64/kernel/kprobes.c @@ -398,7 +398,8 @@ static void kretprobe_trampoline(void) int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { - regs->cr_iip = __kretprobe_trampoline_handler(regs, kretprobe_trampoline, NULL); + regs->cr_iip = __kretprobe_trampoline_handler(regs, + dereference_function_descriptor(kretprobe_trampoline), NULL); /* * By returning a non-zero value, we are telling * kprobe_handler() that we don't want the post_handler @@ -414,7 +415,7 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, ri->fp = NULL; /* Replace the return addr with trampoline addr */ - regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip; + regs->b0 = (unsigned long)dereference_function_descriptor(kretprobe_trampoline); } /* Check the instruction in the slot is break */ @@ -902,14 +903,14 @@ static struct kprobe trampoline_p = { int __init arch_init_kprobes(void) { trampoline_p.addr = - (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip; + dereference_function_descriptor(kretprobe_trampoline); return register_kprobe(&trampoline_p); } int __kprobes arch_trampoline_kprobe(struct kprobe *p) { if (p->addr == - (kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip) + dereference_function_descriptor(kretprobe_trampoline)) return 1; return 0;
Commit e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler") missed to pass the wrong trampoline address (it passes the descriptor address instead of function entry address). This fixes it to pass correct trampoline address to __kretprobe_trampoline_handler(). This also changes to use correct symbol dereference function to get the function address from the kretprobe_trampoline. Fixes: e792ff804f49 ("ia64: kprobes: Use generic kretprobe trampoline handler") Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- Changes in v5: - Fix a compile error typo. --- arch/ia64/kernel/kprobes.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)