Due to lack of the checking and setting-NULL on pointer, there are some
null pointer dereference or page fault bugs were found when insert
module, and fixed by this patch set.
Shang XiaoJing (2):
tracing: kprobe: Fix potential null-ptr-deref on trace_event_file in
kprobe_event_gen_test_exit()
tracing: kprobe: Fix potential null-ptr-deref on trace_array in
kprobe_event_gen_test_exit()
kernel/trace/kprobe_event_gen_test.c | 51 +++++++++++++++++++---------
1 file changed, 35 insertions(+), 16 deletions(-)
--
2.17.1
When trace_get_event_file() failed, gen_kretprobe_test will be assigned
as the error code. If module kprobe_event_gen_test is removed now, the
null pointer dereference will happen in kprobe_event_gen_test_exit().
Check if gen_kprobe_test or gen_kretprobe_test is error code or NULL
before dereference them.
BUG: kernel NULL pointer dereference, address: 0000000000000012
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 3 PID: 2210 Comm: modprobe Not tainted
6.1.0-rc1-00171-g2159299a3b74-dirty #217
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:kprobe_event_gen_test_exit+0x1c/0xb5 [kprobe_event_gen_test]
Code: Unable to access opcode bytes at 0xffffffff9ffffff2.
RSP: 0018:ffffc900015bfeb8 EFLAGS: 00010246
RAX: ffffffffffffffea RBX: ffffffffa0002080 RCX: 0000000000000000
RDX: ffffffffa0001054 RSI: ffffffffa0001064 RDI: ffffffffdfc6349c
RBP: ffffffffa0000000 R08: 0000000000000004 R09: 00000000001e95c0
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000800
R13: ffffffffa0002420 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f56b75be540(0000) GS:ffff88813bc00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff9ffffff2 CR3: 000000010874a006 CR4: 0000000000330ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__x64_sys_delete_module+0x206/0x380
? lockdep_hardirqs_on_prepare+0xd8/0x190
? syscall_enter_from_user_mode+0x1c/0x50
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module")
Signed-off-by: Shang XiaoJing <[email protected]>
---
kernel/trace/kprobe_event_gen_test.c | 44 ++++++++++++++++++----------
1 file changed, 28 insertions(+), 16 deletions(-)
diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
index d81f7c51025c..1c98fafcf333 100644
--- a/kernel/trace/kprobe_event_gen_test.c
+++ b/kernel/trace/kprobe_event_gen_test.c
@@ -73,6 +73,10 @@ static struct trace_event_file *gen_kretprobe_test;
#define KPROBE_GEN_TEST_ARG3 NULL
#endif
+static bool trace_event_file_is_valid(struct trace_event_file *input)
+{
+ return input && !IS_ERR(input);
+}
/*
* Test to make sure we can create a kprobe event, then add more
@@ -217,10 +221,12 @@ static int __init kprobe_event_gen_test_init(void)
ret = test_gen_kretprobe_cmd();
if (ret) {
- WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
- "kprobes",
- "gen_kretprobe_test", false));
- trace_put_event_file(gen_kretprobe_test);
+ if (trace_event_file_is_valid(gen_kretprobe_test)) {
+ WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
+ "kprobes",
+ "gen_kretprobe_test", false));
+ trace_put_event_file(gen_kretprobe_test);
+ }
WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
}
@@ -229,24 +235,30 @@ static int __init kprobe_event_gen_test_init(void)
static void __exit kprobe_event_gen_test_exit(void)
{
- /* Disable the event or you can't remove it */
- WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
- "kprobes",
- "gen_kprobe_test", false));
+ if (trace_event_file_is_valid(gen_kprobe_test)) {
+ /* Disable the event or you can't remove it */
+ WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
+ "kprobes",
+ "gen_kprobe_test", false));
+
+ /* Now give the file and instance back */
+ trace_put_event_file(gen_kprobe_test);
+ }
- /* Now give the file and instance back */
- trace_put_event_file(gen_kprobe_test);
/* Now unregister and free the event */
WARN_ON(kprobe_event_delete("gen_kprobe_test"));
- /* Disable the event or you can't remove it */
- WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
- "kprobes",
- "gen_kretprobe_test", false));
+ if (trace_event_file_is_valid(gen_kretprobe_test)) {
+ /* Disable the event or you can't remove it */
+ WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
+ "kprobes",
+ "gen_kretprobe_test", false));
+
+ /* Now give the file and instance back */
+ trace_put_event_file(gen_kretprobe_test);
+ }
- /* Now give the file and instance back */
- trace_put_event_file(gen_kretprobe_test);
/* Now unregister and free the event */
WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
--
2.17.1
When test_gen_kprobe_cmd() failed after kprobe_event_gen_cmd_end(), it
will goto delete, which will call kprobe_event_delete() and release the
corresponding resource. However, the trace_array in gen_kretprobe_test
will point to the invalid resource. Set gen_kretprobe_test->tr to NULL
after called kprobe_event_delete() and add NULL check when releasing
the module.
BUG: kernel NULL pointer dereference, address: 0000000000000070
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 0 PID: 246 Comm: modprobe Tainted: G W
6.1.0-rc1-00174-g9522dc5c87da-dirty #248
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:__ftrace_set_clr_event_nolock+0x53/0x1b0
Code: e8 82 26 fc ff 49 8b 1e c7 44 24 0c ea ff ff ff 49 39 de 0f 84 3c
01 00 00 c7 44 24 18 00 00 00 00 e8 61 26 fc ff 48 8b 6b 10 <44> 8b 65
70 4c 8b 6d 18 41 f7 c4 00 02 00 00 75 2f
RSP: 0018:ffffc9000159fe00 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88810971d268 RCX: 0000000000000000
RDX: ffff8881080be600 RSI: ffffffff811b48ff RDI: ffff88810971d058
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: ffffc9000159fe58 R11: 0000000000000001 R12: ffffffffa0001064
R13: ffffffffa000106c R14: ffff88810971d238 R15: 0000000000000000
FS: 00007f89eeff6540(0000) GS:ffff88813b600000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000070 CR3: 000000010599e004 CR4: 0000000000330ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__ftrace_set_clr_event+0x3e/0x60
trace_array_set_clr_event+0x35/0x50
? 0xffffffffa0000000
kprobe_event_gen_test_exit+0xcd/0x10b [kprobe_event_gen_test]
__x64_sys_delete_module+0x206/0x380
? lockdep_hardirqs_on_prepare+0xd8/0x190
? syscall_enter_from_user_mode+0x1c/0x50
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f89eeb061b7
Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module")
Signed-off-by: Shang XiaoJing <[email protected]>
---
kernel/trace/kprobe_event_gen_test.c | 29 +++++++++++++++++-----------
1 file changed, 18 insertions(+), 11 deletions(-)
diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
index 1c98fafcf333..277e21e4a63e 100644
--- a/kernel/trace/kprobe_event_gen_test.c
+++ b/kernel/trace/kprobe_event_gen_test.c
@@ -145,6 +145,8 @@ static int __init test_gen_kprobe_cmd(void)
delete:
/* We got an error after creating the event, delete it */
ret = kprobe_event_delete("gen_kprobe_test");
+ if (trace_event_file_is_valid(gen_kprobe_test))
+ gen_kprobe_test->tr = NULL;
goto out;
}
@@ -208,6 +210,8 @@ static int __init test_gen_kretprobe_cmd(void)
delete:
/* We got an error after creating the event, delete it */
ret = kprobe_event_delete("gen_kretprobe_test");
+ if (trace_event_file_is_valid(gen_kretprobe_test))
+ gen_kretprobe_test->tr = NULL;
goto out;
}
@@ -222,9 +226,10 @@ static int __init kprobe_event_gen_test_init(void)
ret = test_gen_kretprobe_cmd();
if (ret) {
if (trace_event_file_is_valid(gen_kretprobe_test)) {
- WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
- "kprobes",
- "gen_kretprobe_test", false));
+ if (gen_kretprobe_test->tr)
+ WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
+ "kprobes",
+ "gen_kretprobe_test", false));
trace_put_event_file(gen_kretprobe_test);
}
WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
@@ -236,10 +241,11 @@ static int __init kprobe_event_gen_test_init(void)
static void __exit kprobe_event_gen_test_exit(void)
{
if (trace_event_file_is_valid(gen_kprobe_test)) {
- /* Disable the event or you can't remove it */
- WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
- "kprobes",
- "gen_kprobe_test", false));
+ if (gen_kprobe_test->tr)
+ /* Disable the event or you can't remove it */
+ WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
+ "kprobes",
+ "gen_kprobe_test", false));
/* Now give the file and instance back */
trace_put_event_file(gen_kprobe_test);
@@ -250,10 +256,11 @@ static void __exit kprobe_event_gen_test_exit(void)
WARN_ON(kprobe_event_delete("gen_kprobe_test"));
if (trace_event_file_is_valid(gen_kretprobe_test)) {
- /* Disable the event or you can't remove it */
- WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
- "kprobes",
- "gen_kretprobe_test", false));
+ if (gen_kretprobe_test->tr)
+ /* Disable the event or you can't remove it */
+ WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
+ "kprobes",
+ "gen_kretprobe_test", false));
/* Now give the file and instance back */
trace_put_event_file(gen_kretprobe_test);
--
2.17.1
On Mon, 7 Nov 2022 15:16:16 +0800
Shang XiaoJing <[email protected]> wrote:
> When trace_get_event_file() failed, gen_kretprobe_test will be assigned
> as the error code. If module kprobe_event_gen_test is removed now, the
> null pointer dereference will happen in kprobe_event_gen_test_exit().
> Check if gen_kprobe_test or gen_kretprobe_test is error code or NULL
> before dereference them.
>
> BUG: kernel NULL pointer dereference, address: 0000000000000012
> PGD 0 P4D 0
> Oops: 0000 [#1] SMP PTI
> CPU: 3 PID: 2210 Comm: modprobe Not tainted
> 6.1.0-rc1-00171-g2159299a3b74-dirty #217
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
> RIP: 0010:kprobe_event_gen_test_exit+0x1c/0xb5 [kprobe_event_gen_test]
> Code: Unable to access opcode bytes at 0xffffffff9ffffff2.
> RSP: 0018:ffffc900015bfeb8 EFLAGS: 00010246
> RAX: ffffffffffffffea RBX: ffffffffa0002080 RCX: 0000000000000000
> RDX: ffffffffa0001054 RSI: ffffffffa0001064 RDI: ffffffffdfc6349c
> RBP: ffffffffa0000000 R08: 0000000000000004 R09: 00000000001e95c0
> R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000800
> R13: ffffffffa0002420 R14: 0000000000000000 R15: 0000000000000000
> FS: 00007f56b75be540(0000) GS:ffff88813bc00000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffffff9ffffff2 CR3: 000000010874a006 CR4: 0000000000330ee0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> __x64_sys_delete_module+0x206/0x380
> ? lockdep_hardirqs_on_prepare+0xd8/0x190
> ? syscall_enter_from_user_mode+0x1c/0x50
> do_syscall_64+0x3f/0x90
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module")
Ah, indeed. If anything wrong in the test code and if the
gen_kprobe_test/gen_kretprobe_test is not initialized, this
can happen.
Cc: [email protected]
Acked-by: Masami Hiramatsu (Google) <[email protected]>
Thank you!
> Signed-off-by: Shang XiaoJing <[email protected]>
> ---
> kernel/trace/kprobe_event_gen_test.c | 44 ++++++++++++++++++----------
> 1 file changed, 28 insertions(+), 16 deletions(-)
>
> diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
> index d81f7c51025c..1c98fafcf333 100644
> --- a/kernel/trace/kprobe_event_gen_test.c
> +++ b/kernel/trace/kprobe_event_gen_test.c
> @@ -73,6 +73,10 @@ static struct trace_event_file *gen_kretprobe_test;
> #define KPROBE_GEN_TEST_ARG3 NULL
> #endif
>
> +static bool trace_event_file_is_valid(struct trace_event_file *input)
> +{
> + return input && !IS_ERR(input);
> +}
>
> /*
> * Test to make sure we can create a kprobe event, then add more
> @@ -217,10 +221,12 @@ static int __init kprobe_event_gen_test_init(void)
>
> ret = test_gen_kretprobe_cmd();
> if (ret) {
> - WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
> - "kprobes",
> - "gen_kretprobe_test", false));
> - trace_put_event_file(gen_kretprobe_test);
> + if (trace_event_file_is_valid(gen_kretprobe_test)) {
> + WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
> + "kprobes",
> + "gen_kretprobe_test", false));
> + trace_put_event_file(gen_kretprobe_test);
> + }
> WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
> }
>
> @@ -229,24 +235,30 @@ static int __init kprobe_event_gen_test_init(void)
>
> static void __exit kprobe_event_gen_test_exit(void)
> {
> - /* Disable the event or you can't remove it */
> - WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
> - "kprobes",
> - "gen_kprobe_test", false));
> + if (trace_event_file_is_valid(gen_kprobe_test)) {
> + /* Disable the event or you can't remove it */
> + WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
> + "kprobes",
> + "gen_kprobe_test", false));
> +
> + /* Now give the file and instance back */
> + trace_put_event_file(gen_kprobe_test);
> + }
>
> - /* Now give the file and instance back */
> - trace_put_event_file(gen_kprobe_test);
>
> /* Now unregister and free the event */
> WARN_ON(kprobe_event_delete("gen_kprobe_test"));
>
> - /* Disable the event or you can't remove it */
> - WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
> - "kprobes",
> - "gen_kretprobe_test", false));
> + if (trace_event_file_is_valid(gen_kretprobe_test)) {
> + /* Disable the event or you can't remove it */
> + WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
> + "kprobes",
> + "gen_kretprobe_test", false));
> +
> + /* Now give the file and instance back */
> + trace_put_event_file(gen_kretprobe_test);
> + }
>
> - /* Now give the file and instance back */
> - trace_put_event_file(gen_kretprobe_test);
>
> /* Now unregister and free the event */
> WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
> --
> 2.17.1
>
--
Masami Hiramatsu (Google) <[email protected]>
On 2022/11/7 21:25, Masami Hiramatsu (Google) wrote:
> On Mon, 7 Nov 2022 15:16:16 +0800
> Shang XiaoJing <[email protected]> wrote:
>
>> When trace_get_event_file() failed, gen_kretprobe_test will be assigned
>> as the error code. If module kprobe_event_gen_test is removed now, the
>> null pointer dereference will happen in kprobe_event_gen_test_exit().
>> Check if gen_kprobe_test or gen_kretprobe_test is error code or NULL
>> before dereference them.
>>
>> BUG: kernel NULL pointer dereference, address: 0000000000000012
>> PGD 0 P4D 0
>> Oops: 0000 [#1] SMP PTI
>> CPU: 3 PID: 2210 Comm: modprobe Not tainted
>> 6.1.0-rc1-00171-g2159299a3b74-dirty #217
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
>> rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
>> RIP: 0010:kprobe_event_gen_test_exit+0x1c/0xb5 [kprobe_event_gen_test]
>> Code: Unable to access opcode bytes at 0xffffffff9ffffff2.
>> RSP: 0018:ffffc900015bfeb8 EFLAGS: 00010246
>> RAX: ffffffffffffffea RBX: ffffffffa0002080 RCX: 0000000000000000
>> RDX: ffffffffa0001054 RSI: ffffffffa0001064 RDI: ffffffffdfc6349c
>> RBP: ffffffffa0000000 R08: 0000000000000004 R09: 00000000001e95c0
>> R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000800
>> R13: ffffffffa0002420 R14: 0000000000000000 R15: 0000000000000000
>> FS: 00007f56b75be540(0000) GS:ffff88813bc00000(0000)
>> knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: ffffffff9ffffff2 CR3: 000000010874a006 CR4: 0000000000330ee0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> <TASK>
>> __x64_sys_delete_module+0x206/0x380
>> ? lockdep_hardirqs_on_prepare+0xd8/0x190
>> ? syscall_enter_from_user_mode+0x1c/0x50
>> do_syscall_64+0x3f/0x90
>> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>>
>> Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module")
>
> Ah, indeed. If anything wrong in the test code and if the
> gen_kprobe_test/gen_kretprobe_test is not initialized, this
> can happen.
>
> Cc: [email protected]
> Acked-by: Masami Hiramatsu (Google) <[email protected]>
>
> Thank you!
>
Thanks for the review, will add the Tag in v2.
Thanks,
--
Shang XiaoJing
Hi,
On 2022/11/7 21:38, Masami Hiramatsu (Google) wrote:
> Hi,
>
> On Mon, 7 Nov 2022 15:16:17 +0800
> Shang XiaoJing <[email protected]> wrote:
>
>> When test_gen_kprobe_cmd() failed after kprobe_event_gen_cmd_end(), it
>> will goto delete, which will call kprobe_event_delete() and release the
>> corresponding resource. However, the trace_array in gen_kretprobe_test
>> will point to the invalid resource. Set gen_kretprobe_test->tr to NULL
>> after called kprobe_event_delete() and add NULL check when releasing
>> the module.
>>
>> BUG: kernel NULL pointer dereference, address: 0000000000000070
>> PGD 0 P4D 0
>> Oops: 0000 [#1] SMP PTI
>> CPU: 0 PID: 246 Comm: modprobe Tainted: G W
>> 6.1.0-rc1-00174-g9522dc5c87da-dirty #248
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
>> rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
>> RIP: 0010:__ftrace_set_clr_event_nolock+0x53/0x1b0
>> Code: e8 82 26 fc ff 49 8b 1e c7 44 24 0c ea ff ff ff 49 39 de 0f 84 3c
>> 01 00 00 c7 44 24 18 00 00 00 00 e8 61 26 fc ff 48 8b 6b 10 <44> 8b 65
>> 70 4c 8b 6d 18 41 f7 c4 00 02 00 00 75 2f
>> RSP: 0018:ffffc9000159fe00 EFLAGS: 00010293
>> RAX: 0000000000000000 RBX: ffff88810971d268 RCX: 0000000000000000
>> RDX: ffff8881080be600 RSI: ffffffff811b48ff RDI: ffff88810971d058
>> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
>> R10: ffffc9000159fe58 R11: 0000000000000001 R12: ffffffffa0001064
>> R13: ffffffffa000106c R14: ffff88810971d238 R15: 0000000000000000
>> FS: 00007f89eeff6540(0000) GS:ffff88813b600000(0000)
>> knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000000000070 CR3: 000000010599e004 CR4: 0000000000330ef0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> <TASK>
>> __ftrace_set_clr_event+0x3e/0x60
>> trace_array_set_clr_event+0x35/0x50
>> ? 0xffffffffa0000000
>> kprobe_event_gen_test_exit+0xcd/0x10b [kprobe_event_gen_test]
>> __x64_sys_delete_module+0x206/0x380
>> ? lockdep_hardirqs_on_prepare+0xd8/0x190
>> ? syscall_enter_from_user_mode+0x1c/0x50
>> do_syscall_64+0x3f/0x90
>> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>> RIP: 0033:0x7f89eeb061b7
>>
>> Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module")
>> Signed-off-by: Shang XiaoJing <[email protected]>
>> ---
>> kernel/trace/kprobe_event_gen_test.c | 29 +++++++++++++++++-----------
>> 1 file changed, 18 insertions(+), 11 deletions(-)
>>
>> diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
>> index 1c98fafcf333..277e21e4a63e 100644
>> --- a/kernel/trace/kprobe_event_gen_test.c
>> +++ b/kernel/trace/kprobe_event_gen_test.c
>> @@ -145,6 +145,8 @@ static int __init test_gen_kprobe_cmd(void)
>> delete:
>> /* We got an error after creating the event, delete it */
>> ret = kprobe_event_delete("gen_kprobe_test");
>> + if (trace_event_file_is_valid(gen_kprobe_test))
>> + gen_kprobe_test->tr = NULL;
>
> I think the correct fix should be
>
> if (trace_event_file_is_valid(gen_kprobe_test)) {
> trace_put_event_file(gen_kprobe_test);
> gen_kprobe_test = NULL;
> }
> ret = kprobe_event_delete("gen_kprobe_test");
>
> Since the gen_kprobe_event is owned by ftrace subsystem, the test
> code should not change the tr field.
>
When trace_array_set_clr_event() failed, it already called
trace_put_event_file(), maybe we only need set gen_kprobe_test to NULL.
>> goto out;
>> }
>>
>> @@ -208,6 +210,8 @@ static int __init test_gen_kretprobe_cmd(void)
>> delete:
>> /* We got an error after creating the event, delete it */
>> ret = kprobe_event_delete("gen_kretprobe_test");
>> + if (trace_event_file_is_valid(gen_kretprobe_test))
>> + gen_kretprobe_test->tr = NULL;
>
> Ditto. >
> And then, below changes are not required.
Yes, will fix in v2, thanks for the review.
Thanks,
--
Shang XiaoJing
Hi,
On Mon, 7 Nov 2022 15:16:17 +0800
Shang XiaoJing <[email protected]> wrote:
> When test_gen_kprobe_cmd() failed after kprobe_event_gen_cmd_end(), it
> will goto delete, which will call kprobe_event_delete() and release the
> corresponding resource. However, the trace_array in gen_kretprobe_test
> will point to the invalid resource. Set gen_kretprobe_test->tr to NULL
> after called kprobe_event_delete() and add NULL check when releasing
> the module.
>
> BUG: kernel NULL pointer dereference, address: 0000000000000070
> PGD 0 P4D 0
> Oops: 0000 [#1] SMP PTI
> CPU: 0 PID: 246 Comm: modprobe Tainted: G W
> 6.1.0-rc1-00174-g9522dc5c87da-dirty #248
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
> RIP: 0010:__ftrace_set_clr_event_nolock+0x53/0x1b0
> Code: e8 82 26 fc ff 49 8b 1e c7 44 24 0c ea ff ff ff 49 39 de 0f 84 3c
> 01 00 00 c7 44 24 18 00 00 00 00 e8 61 26 fc ff 48 8b 6b 10 <44> 8b 65
> 70 4c 8b 6d 18 41 f7 c4 00 02 00 00 75 2f
> RSP: 0018:ffffc9000159fe00 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: ffff88810971d268 RCX: 0000000000000000
> RDX: ffff8881080be600 RSI: ffffffff811b48ff RDI: ffff88810971d058
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
> R10: ffffc9000159fe58 R11: 0000000000000001 R12: ffffffffa0001064
> R13: ffffffffa000106c R14: ffff88810971d238 R15: 0000000000000000
> FS: 00007f89eeff6540(0000) GS:ffff88813b600000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000070 CR3: 000000010599e004 CR4: 0000000000330ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> __ftrace_set_clr_event+0x3e/0x60
> trace_array_set_clr_event+0x35/0x50
> ? 0xffffffffa0000000
> kprobe_event_gen_test_exit+0xcd/0x10b [kprobe_event_gen_test]
> __x64_sys_delete_module+0x206/0x380
> ? lockdep_hardirqs_on_prepare+0xd8/0x190
> ? syscall_enter_from_user_mode+0x1c/0x50
> do_syscall_64+0x3f/0x90
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7f89eeb061b7
>
> Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module")
> Signed-off-by: Shang XiaoJing <[email protected]>
> ---
> kernel/trace/kprobe_event_gen_test.c | 29 +++++++++++++++++-----------
> 1 file changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
> index 1c98fafcf333..277e21e4a63e 100644
> --- a/kernel/trace/kprobe_event_gen_test.c
> +++ b/kernel/trace/kprobe_event_gen_test.c
> @@ -145,6 +145,8 @@ static int __init test_gen_kprobe_cmd(void)
> delete:
> /* We got an error after creating the event, delete it */
> ret = kprobe_event_delete("gen_kprobe_test");
> + if (trace_event_file_is_valid(gen_kprobe_test))
> + gen_kprobe_test->tr = NULL;
I think the correct fix should be
if (trace_event_file_is_valid(gen_kprobe_test)) {
trace_put_event_file(gen_kprobe_test);
gen_kprobe_test = NULL;
}
ret = kprobe_event_delete("gen_kprobe_test");
Since the gen_kprobe_event is owned by ftrace subsystem, the test
code should not change the tr field.
> goto out;
> }
>
> @@ -208,6 +210,8 @@ static int __init test_gen_kretprobe_cmd(void)
> delete:
> /* We got an error after creating the event, delete it */
> ret = kprobe_event_delete("gen_kretprobe_test");
> + if (trace_event_file_is_valid(gen_kretprobe_test))
> + gen_kretprobe_test->tr = NULL;
Ditto.
And then, below changes are not required.
Thank you,
> goto out;
> }
>
> @@ -222,9 +226,10 @@ static int __init kprobe_event_gen_test_init(void)
> ret = test_gen_kretprobe_cmd();
> if (ret) {
> if (trace_event_file_is_valid(gen_kretprobe_test)) {
> - WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
> - "kprobes",
> - "gen_kretprobe_test", false));
> + if (gen_kretprobe_test->tr)
> + WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
> + "kprobes",
> + "gen_kretprobe_test", false));
> trace_put_event_file(gen_kretprobe_test);
> }
> WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
> @@ -236,10 +241,11 @@ static int __init kprobe_event_gen_test_init(void)
> static void __exit kprobe_event_gen_test_exit(void)
> {
> if (trace_event_file_is_valid(gen_kprobe_test)) {
> - /* Disable the event or you can't remove it */
> - WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
> - "kprobes",
> - "gen_kprobe_test", false));
> + if (gen_kprobe_test->tr)
> + /* Disable the event or you can't remove it */
> + WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
> + "kprobes",
> + "gen_kprobe_test", false));
>
> /* Now give the file and instance back */
> trace_put_event_file(gen_kprobe_test);
> @@ -250,10 +256,11 @@ static void __exit kprobe_event_gen_test_exit(void)
> WARN_ON(kprobe_event_delete("gen_kprobe_test"));
>
> if (trace_event_file_is_valid(gen_kretprobe_test)) {
> - /* Disable the event or you can't remove it */
> - WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
> - "kprobes",
> - "gen_kretprobe_test", false));
> + if (gen_kretprobe_test->tr)
> + /* Disable the event or you can't remove it */
> + WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
> + "kprobes",
> + "gen_kretprobe_test", false));
>
> /* Now give the file and instance back */
> trace_put_event_file(gen_kretprobe_test);
> --
> 2.17.1
>
--
Masami Hiramatsu (Google) <[email protected]>
On Mon, 7 Nov 2022 21:47:10 +0800
shangxiaojing <[email protected]> wrote:
> Hi,
>
> On 2022/11/7 21:38, Masami Hiramatsu (Google) wrote:
> > Hi,
> >
> > On Mon, 7 Nov 2022 15:16:17 +0800
> > Shang XiaoJing <[email protected]> wrote:
> >
> >> When test_gen_kprobe_cmd() failed after kprobe_event_gen_cmd_end(), it
> >> will goto delete, which will call kprobe_event_delete() and release the
> >> corresponding resource. However, the trace_array in gen_kretprobe_test
> >> will point to the invalid resource. Set gen_kretprobe_test->tr to NULL
> >> after called kprobe_event_delete() and add NULL check when releasing
> >> the module.
> >>
> >> BUG: kernel NULL pointer dereference, address: 0000000000000070
> >> PGD 0 P4D 0
> >> Oops: 0000 [#1] SMP PTI
> >> CPU: 0 PID: 246 Comm: modprobe Tainted: G W
> >> 6.1.0-rc1-00174-g9522dc5c87da-dirty #248
> >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> >> rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
> >> RIP: 0010:__ftrace_set_clr_event_nolock+0x53/0x1b0
> >> Code: e8 82 26 fc ff 49 8b 1e c7 44 24 0c ea ff ff ff 49 39 de 0f 84 3c
> >> 01 00 00 c7 44 24 18 00 00 00 00 e8 61 26 fc ff 48 8b 6b 10 <44> 8b 65
> >> 70 4c 8b 6d 18 41 f7 c4 00 02 00 00 75 2f
> >> RSP: 0018:ffffc9000159fe00 EFLAGS: 00010293
> >> RAX: 0000000000000000 RBX: ffff88810971d268 RCX: 0000000000000000
> >> RDX: ffff8881080be600 RSI: ffffffff811b48ff RDI: ffff88810971d058
> >> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
> >> R10: ffffc9000159fe58 R11: 0000000000000001 R12: ffffffffa0001064
> >> R13: ffffffffa000106c R14: ffff88810971d238 R15: 0000000000000000
> >> FS: 00007f89eeff6540(0000) GS:ffff88813b600000(0000)
> >> knlGS:0000000000000000
> >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> CR2: 0000000000000070 CR3: 000000010599e004 CR4: 0000000000330ef0
> >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> >> Call Trace:
> >> <TASK>
> >> __ftrace_set_clr_event+0x3e/0x60
> >> trace_array_set_clr_event+0x35/0x50
> >> ? 0xffffffffa0000000
> >> kprobe_event_gen_test_exit+0xcd/0x10b [kprobe_event_gen_test]
> >> __x64_sys_delete_module+0x206/0x380
> >> ? lockdep_hardirqs_on_prepare+0xd8/0x190
> >> ? syscall_enter_from_user_mode+0x1c/0x50
> >> do_syscall_64+0x3f/0x90
> >> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> >> RIP: 0033:0x7f89eeb061b7
> >>
> >> Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module")
> >> Signed-off-by: Shang XiaoJing <[email protected]>
> >> ---
> >> kernel/trace/kprobe_event_gen_test.c | 29 +++++++++++++++++-----------
> >> 1 file changed, 18 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
> >> index 1c98fafcf333..277e21e4a63e 100644
> >> --- a/kernel/trace/kprobe_event_gen_test.c
> >> +++ b/kernel/trace/kprobe_event_gen_test.c
> >> @@ -145,6 +145,8 @@ static int __init test_gen_kprobe_cmd(void)
> >> delete:
> >> /* We got an error after creating the event, delete it */
> >> ret = kprobe_event_delete("gen_kprobe_test");
> >> + if (trace_event_file_is_valid(gen_kprobe_test))
> >> + gen_kprobe_test->tr = NULL;
> >
> > I think the correct fix should be
> >
> > if (trace_event_file_is_valid(gen_kprobe_test)) {
> > trace_put_event_file(gen_kprobe_test);
> > gen_kprobe_test = NULL;
> > }
> > ret = kprobe_event_delete("gen_kprobe_test");
> >
> > Since the gen_kprobe_event is owned by ftrace subsystem, the test
> > code should not change the tr field.
> >
> When trace_array_set_clr_event() failed, it already called
> trace_put_event_file(), maybe we only need set gen_kprobe_test to NULL.
Ah, OK. That should work.
Thank you,
>
> >> goto out;
> >> }
> >>
> >> @@ -208,6 +210,8 @@ static int __init test_gen_kretprobe_cmd(void)
> >> delete:
> >> /* We got an error after creating the event, delete it */
> >> ret = kprobe_event_delete("gen_kretprobe_test");
> >> + if (trace_event_file_is_valid(gen_kretprobe_test))
> >> + gen_kretprobe_test->tr = NULL;
> >
> > Ditto. >
> > And then, below changes are not required.
>
> Yes, will fix in v2, thanks for the review.
>
> Thanks,
> --
> Shang XiaoJing
--
Masami Hiramatsu (Google) <[email protected]>