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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2017-02-13 18:05:59 +0300 |
|---|---|---|
| committer | Jon Medhurst <tixy@linaro.org> | 2017-03-21 19:24:18 +0300 |
| commit | 06553175f585b52509c7df37d6f4a50aacb7b211 (patch) | |
| tree | e0ccf491aef5454736ec3c607651bccb8cb4dd1c /arch/arm/probes | |
| parent | 91fc862c613ab7a0ef6b0b7755c33619127f4e5a (diff) | |
| download | linux-06553175f585b52509c7df37d6f4a50aacb7b211.tar.xz | |
arm: kprobes: Fix the return address of multiple kretprobes
This is arm port of commit 737480a0d525 ("kprobes/x86:
Fix the return address of multiple kretprobes").
Fix the return address of subsequent kretprobes when multiple
kretprobes are set on the same function.
For example:
# cd /sys/kernel/debug/tracing
# echo "r:event1 sys_symlink" > kprobe_events
# echo "r:event2 sys_symlink" >> kprobe_events
# echo 1 > events/kprobes/enable
# ln -s /tmp/foo /tmp/bar
(without this patch)
# cat trace | grep -v ^#
ln-82 [000] dn.2 68.446525: event1: (kretprobe_trampoline+0x0/0x18 <- SyS_symlink)
ln-82 [000] dn.2 68.447831: event2: (ret_fast_syscall+0x0/0x1c <- SyS_symlink)
(with this patch)
# cat trace | grep -v ^#
ln-81 [000] dn.1 39.463469: event1: (ret_fast_syscall+0x0/0x1c <- SyS_symlink)
ln-81 [000] dn.1 39.464701: event2: (ret_fast_syscall+0x0/0x1c <- SyS_symlink)
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: KUMANO Syuhei <kumano.prog@gmail.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
Diffstat (limited to 'arch/arm/probes')
| -rw-r--r-- | arch/arm/probes/kprobes/core.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c index 269f66e66ff5..ad1f4e6a9e33 100644 --- a/arch/arm/probes/kprobes/core.c +++ b/arch/arm/probes/kprobes/core.c @@ -441,6 +441,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) struct hlist_node *tmp; unsigned long flags, orig_ret_address = 0; unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline; + kprobe_opcode_t *correct_ret_addr = NULL; INIT_HLIST_HEAD(&empty_rp); kretprobe_hash_lock(current, &head, &flags); @@ -463,14 +464,34 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) /* another task is sharing our hash bucket */ continue; + orig_ret_address = (unsigned long)ri->ret_addr; + + if (orig_ret_address != trampoline_address) + /* + * This is the real return address. Any other + * instances associated with this task are for + * other calls deeper on the call stack + */ + break; + } + + kretprobe_assert(ri, orig_ret_address, trampoline_address); + + correct_ret_addr = ri->ret_addr; + hlist_for_each_entry_safe(ri, tmp, head, hlist) { + if (ri->task != current) + /* another task is sharing our hash bucket */ + continue; + + orig_ret_address = (unsigned long)ri->ret_addr; if (ri->rp && ri->rp->handler) { __this_cpu_write(current_kprobe, &ri->rp->kp); get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE; + ri->ret_addr = correct_ret_addr; ri->rp->handler(ri, regs); __this_cpu_write(current_kprobe, NULL); } - orig_ret_address = (unsigned long)ri->ret_addr; recycle_rp_inst(ri, &empty_rp); if (orig_ret_address != trampoline_address) @@ -482,7 +503,6 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs) break; } - kretprobe_assert(ri, orig_ret_address, trampoline_address); kretprobe_hash_unlock(current, &flags); hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) { |