In register_synth_event(), if set_synth_event_print_fmt() failed, then
both trace_remove_event_call() and unregister_trace_event() will be
called, which means the trace_event_call will call
__unregister_trace_event() twice. As the result, the second unregister
will causes the wild-memory-access.
register_synth_event
set_synth_event_print_fmt failed
trace_remove_event_call
event_remove
if call->event.funcs then
__unregister_trace_event (first call)
unregister_trace_event
__unregister_trace_event (second call)
Fix the bug by avoiding to call the second __unregister_trace_event() by
checking if the first one is called.
general protection fault, probably for non-canonical address
0xfbd59c0000000024: 0000 [#1] SMP KASAN PTI
KASAN: maybe wild-memory-access in range
[0xdead000000000120-0xdead000000000127]
CPU: 0 PID: 3807 Comm: modprobe Not tainted
6.1.0-rc1-00186-g76f33a7eedb4 #299
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:unregister_trace_event+0x6e/0x280
Code: 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 0e 02 00 00 48
b8 00 00 00 00 00 fc ff df 4c 8b 63 08 4c 89 e2 48 c1 ea 03 <80> 3c 02
00 0f 85 e2 01 00 00 49 89 2c 24 48 85 ed 74 28 e8 7a 9b
RSP: 0018:ffff88810413f370 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: ffff888105d050b0 RCX: 0000000000000000
RDX: 1bd5a00000000024 RSI: ffff888119e276e0 RDI: ffffffff835a8b20
RBP: dead000000000100 R08: 0000000000000000 R09: fffffbfff0913481
R10: ffffffff8489a407 R11: fffffbfff0913480 R12: dead000000000122
R13: ffff888105d050b8 R14: 0000000000000000 R15: ffff888105d05028
FS: 00007f7823e8d540(0000) GS:ffff888119e00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7823e7ebec CR3: 000000010a058002 CR4: 0000000000330ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__create_synth_event+0x1e37/0x1eb0
create_or_delete_synth_event+0x110/0x250
synth_event_run_command+0x2f/0x110
test_gen_synth_cmd+0x170/0x2eb [synth_event_gen_test]
synth_event_gen_test_init+0x76/0x9bc [synth_event_gen_test]
do_one_initcall+0xdb/0x480
do_init_module+0x1cf/0x680
load_module+0x6a50/0x70a0
__do_sys_finit_module+0x12f/0x1c0
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes: 4b147936fa50 ("tracing: Add support for 'synthetic' events")
Signed-off-by: Shang XiaoJing <[email protected]>
Cc: [email protected]
---
changes in v2:
- remove the redundant if statement.
---
kernel/trace/trace_events_synth.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index e310052dc83c..63eccc50b492 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -829,8 +829,9 @@ static int register_synth_event(struct synth_event *event)
ret = set_synth_event_print_fmt(call);
if (ret < 0) {
+ /* unregister_trace_event() will be called inside */
trace_remove_event_call(call);
- goto err;
+ return ret;
}
out:
return ret;
--
2.17.1
Hi Shang,
On Sun, 2022-11-13 at 15:09 +0800, Shang XiaoJing wrote:
> In register_synth_event(), if set_synth_event_print_fmt() failed,
> then
> both trace_remove_event_call() and unregister_trace_event() will be
> called, which means the trace_event_call will call
> __unregister_trace_event() twice. As the result, the second
> unregister
> will causes the wild-memory-access.
>
> register_synth_event
> set_synth_event_print_fmt failed
> trace_remove_event_call
> event_remove
> if call->event.funcs then
> __unregister_trace_event (first call)
> unregister_trace_event
> __unregister_trace_event (second call)
>
> Fix the bug by avoiding to call the second __unregister_trace_event()
> by
> checking if the first one is called.
>
> general protection fault, probably for non-canonical address
> 0xfbd59c0000000024: 0000 [#1] SMP KASAN PTI
> KASAN: maybe wild-memory-access in range
> [0xdead000000000120-0xdead000000000127]
> CPU: 0 PID: 3807 Comm: modprobe Not tainted
> 6.1.0-rc1-00186-g76f33a7eedb4 #299
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
> RIP: 0010:unregister_trace_event+0x6e/0x280
> Code: 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 0e 02 00 00
> 48
> b8 00 00 00 00 00 fc ff df 4c 8b 63 08 4c 89 e2 48 c1 ea 03 <80> 3c
> 02
> 00 0f 85 e2 01 00 00 49 89 2c 24 48 85 ed 74 28 e8 7a 9b
> RSP: 0018:ffff88810413f370 EFLAGS: 00010a06
> RAX: dffffc0000000000 RBX: ffff888105d050b0 RCX: 0000000000000000
> RDX: 1bd5a00000000024 RSI: ffff888119e276e0 RDI: ffffffff835a8b20
> RBP: dead000000000100 R08: 0000000000000000 R09: fffffbfff0913481
> R10: ffffffff8489a407 R11: fffffbfff0913480 R12: dead000000000122
> R13: ffff888105d050b8 R14: 0000000000000000 R15: ffff888105d05028
> FS: 00007f7823e8d540(0000) GS:ffff888119e00000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f7823e7ebec CR3: 000000010a058002 CR4: 0000000000330ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> __create_synth_event+0x1e37/0x1eb0
> create_or_delete_synth_event+0x110/0x250
> synth_event_run_command+0x2f/0x110
> test_gen_synth_cmd+0x170/0x2eb [synth_event_gen_test]
> synth_event_gen_test_init+0x76/0x9bc [synth_event_gen_test]
> do_one_initcall+0xdb/0x480
> do_init_module+0x1cf/0x680
> load_module+0x6a50/0x70a0
> __do_sys_finit_module+0x12f/0x1c0
> do_syscall_64+0x3f/0x90
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Fixes: 4b147936fa50 ("tracing: Add support for 'synthetic' events")
> Signed-off-by: Shang XiaoJing <[email protected]>
> Cc: [email protected]
> ---
> changes in v2:
> - remove the redundant if statement.
> ---
> kernel/trace/trace_events_synth.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/trace/trace_events_synth.c
> b/kernel/trace/trace_events_synth.c
> index e310052dc83c..63eccc50b492 100644
> --- a/kernel/trace/trace_events_synth.c
> +++ b/kernel/trace/trace_events_synth.c
> @@ -829,8 +829,9 @@ static int register_synth_event(struct
> synth_event *event)
>
> ret = set_synth_event_print_fmt(call);
> if (ret < 0) {
> + /* unregister_trace_event() will be called inside */
> trace_remove_event_call(call);
> - goto err;
> + return ret;
Since 'return ret;' is already the next line below, you can just get
rid of this one.
Thanks,
Tom
> }
> out:
> return ret;