* [PATCH] crypto: ccp - Fix crash when rebind ccp device for ccp.ko
@ 2025-06-23 6:25 Mengbiao Xiong
2025-06-23 17:17 ` Tom Lendacky
0 siblings, 1 reply; 3+ messages in thread
From: Mengbiao Xiong @ 2025-06-23 6:25 UTC (permalink / raw)
To: herbert, davem
Cc: thomas.lendacky, john.allen, gary.hook, linux-crypto,
linux-kernel, Mengbiao Xiong
When CONFIG_CRYPTO_DEV_CCP_DEBUGFS is enabled, rebinding
the ccp device causes the following crash:
$ echo '0000:0a:00.2' > /sys/bus/pci/drivers/ccp/unbind
$ echo '0000:0a:00.2' > /sys/bus/pci/drivers/ccp/bind
[ 204.976930] BUG: kernel NULL pointer dereference, address: 0000000000000098
[ 204.978026] #PF: supervisor write access in kernel mode
[ 204.979126] #PF: error_code(0x0002) - not-present page
[ 204.980226] PGD 0 P4D 0
[ 204.981317] Oops: Oops: 0002 [#1] SMP NOPTI
...
[ 204.997852] Call Trace:
[ 204.999074] <TASK>
[ 205.000297] start_creating+0x9f/0x1c0
[ 205.001533] debugfs_create_dir+0x1f/0x170
[ 205.002769] ? srso_return_thunk+0x5/0x5f
[ 205.004000] ccp5_debugfs_setup+0x87/0x170 [ccp]
[ 205.005241] ccp5_init+0x8b2/0x960 [ccp]
[ 205.006469] ccp_dev_init+0xd4/0x150 [ccp]
[ 205.007709] sp_init+0x5f/0x80 [ccp]
[ 205.008942] sp_pci_probe+0x283/0x2e0 [ccp]
[ 205.010165] ? srso_return_thunk+0x5/0x5f
[ 205.011376] local_pci_probe+0x4f/0xb0
[ 205.012584] pci_device_probe+0xdb/0x230
[ 205.013810] really_probe+0xed/0x380
[ 205.015024] __driver_probe_device+0x7e/0x160
[ 205.016240] device_driver_attach+0x2f/0x60
[ 205.017457] bind_store+0x7c/0xb0
[ 205.018663] drv_attr_store+0x28/0x40
[ 205.019868] sysfs_kf_write+0x5f/0x70
[ 205.021065] kernfs_fop_write_iter+0x145/0x1d0
[ 205.022267] vfs_write+0x308/0x440
[ 205.023453] ksys_write+0x6d/0xe0
[ 205.024616] __x64_sys_write+0x1e/0x30
[ 205.025778] x64_sys_call+0x16ba/0x2150
[ 205.026942] do_syscall_64+0x56/0x1e0
[ 205.028108] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 205.029276] RIP: 0033:0x7fbc36f10104
[ 205.030420] Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 e1 08 2e 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5
This patch sets ccp_debugfs_dir to NULL after destroying it in
ccp5_debugfs_destroy, allowing the directory dentry to be
recreated when rebinding the ccp device.
Tested on AMD Ryzen 7 1700X.
Fixes: 3cdbe346ed3f ("crypto: ccp - Add debugfs entries for CCP information")
Signed-off-by: Mengbiao Xiong <xisme1998@gmail.com>
---
drivers/crypto/ccp/ccp-debugfs.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/crypto/ccp/ccp-debugfs.c b/drivers/crypto/ccp/ccp-debugfs.c
index a1055554b..0d432f3c4 100644
--- a/drivers/crypto/ccp/ccp-debugfs.c
+++ b/drivers/crypto/ccp/ccp-debugfs.c
@@ -320,4 +320,5 @@ void ccp5_debugfs_setup(struct ccp_device *ccp)
void ccp5_debugfs_destroy(void)
{
debugfs_remove_recursive(ccp_debugfs_dir);
+ ccp_debugfs_dir = NULL;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] crypto: ccp - Fix crash when rebind ccp device for ccp.ko
2025-06-23 6:25 [PATCH] crypto: ccp - Fix crash when rebind ccp device for ccp.ko Mengbiao Xiong
@ 2025-06-23 17:17 ` Tom Lendacky
2025-06-24 6:04 ` 1998 Xisme
0 siblings, 1 reply; 3+ messages in thread
From: Tom Lendacky @ 2025-06-23 17:17 UTC (permalink / raw)
To: Mengbiao Xiong, herbert, davem; +Cc: john.allen, linux-crypto, linux-kernel
On 6/23/25 01:25, Mengbiao Xiong wrote:
> When CONFIG_CRYPTO_DEV_CCP_DEBUGFS is enabled, rebinding
> the ccp device causes the following crash:
>
> $ echo '0000:0a:00.2' > /sys/bus/pci/drivers/ccp/unbind
> $ echo '0000:0a:00.2' > /sys/bus/pci/drivers/ccp/bind
>
> [ 204.976930] BUG: kernel NULL pointer dereference, address: 0000000000000098
> [ 204.978026] #PF: supervisor write access in kernel mode
> [ 204.979126] #PF: error_code(0x0002) - not-present page
> [ 204.980226] PGD 0 P4D 0
> [ 204.981317] Oops: Oops: 0002 [#1] SMP NOPTI
> ...
> [ 204.997852] Call Trace:
> [ 204.999074] <TASK>
> [ 205.000297] start_creating+0x9f/0x1c0
> [ 205.001533] debugfs_create_dir+0x1f/0x170
> [ 205.002769] ? srso_return_thunk+0x5/0x5f
> [ 205.004000] ccp5_debugfs_setup+0x87/0x170 [ccp]
> [ 205.005241] ccp5_init+0x8b2/0x960 [ccp]
> [ 205.006469] ccp_dev_init+0xd4/0x150 [ccp]
> [ 205.007709] sp_init+0x5f/0x80 [ccp]
> [ 205.008942] sp_pci_probe+0x283/0x2e0 [ccp]
> [ 205.010165] ? srso_return_thunk+0x5/0x5f
> [ 205.011376] local_pci_probe+0x4f/0xb0
> [ 205.012584] pci_device_probe+0xdb/0x230
> [ 205.013810] really_probe+0xed/0x380
> [ 205.015024] __driver_probe_device+0x7e/0x160
> [ 205.016240] device_driver_attach+0x2f/0x60
> [ 205.017457] bind_store+0x7c/0xb0
> [ 205.018663] drv_attr_store+0x28/0x40
> [ 205.019868] sysfs_kf_write+0x5f/0x70
> [ 205.021065] kernfs_fop_write_iter+0x145/0x1d0
> [ 205.022267] vfs_write+0x308/0x440
> [ 205.023453] ksys_write+0x6d/0xe0
> [ 205.024616] __x64_sys_write+0x1e/0x30
> [ 205.025778] x64_sys_call+0x16ba/0x2150
> [ 205.026942] do_syscall_64+0x56/0x1e0
> [ 205.028108] entry_SYSCALL_64_after_hwframe+0x76/0x7e
> [ 205.029276] RIP: 0033:0x7fbc36f10104
> [ 205.030420] Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 e1 08 2e 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5
>
> This patch sets ccp_debugfs_dir to NULL after destroying it in
> ccp5_debugfs_destroy, allowing the directory dentry to be
> recreated when rebinding the ccp device.
>
> Tested on AMD Ryzen 7 1700X.
>
> Fixes: 3cdbe346ed3f ("crypto: ccp - Add debugfs entries for CCP information")
> Signed-off-by: Mengbiao Xiong <xisme1998@gmail.com>
> ---
> drivers/crypto/ccp/ccp-debugfs.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/crypto/ccp/ccp-debugfs.c b/drivers/crypto/ccp/ccp-debugfs.c
> index a1055554b..0d432f3c4 100644
> --- a/drivers/crypto/ccp/ccp-debugfs.c
> +++ b/drivers/crypto/ccp/ccp-debugfs.c
> @@ -320,4 +320,5 @@ void ccp5_debugfs_setup(struct ccp_device *ccp)
> void ccp5_debugfs_destroy(void)
> {
> debugfs_remove_recursive(ccp_debugfs_dir);
> + ccp_debugfs_dir = NULL;
Hmmm... it seems like this should be protected by the mutex similar to how
ccp5_debugfs_setup() is, right?
Maybe something like:
mutex_lock(&ccp_debugfs_lock);
if (ccp_debugfs_dir) {
debugfs_remove_recursive(ccp_debugfs_dir);
ccp_debugfs_dir = NULL;
}
mutex_unlock(&ccp_debugfs_lock);
That should also fix the issue, thoughts?
Thanks,
Tom
> }
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] crypto: ccp - Fix crash when rebind ccp device for ccp.ko
2025-06-23 17:17 ` Tom Lendacky
@ 2025-06-24 6:04 ` 1998 Xisme
0 siblings, 0 replies; 3+ messages in thread
From: 1998 Xisme @ 2025-06-24 6:04 UTC (permalink / raw)
To: Tom Lendacky, herbert, davem; +Cc: john.allen, linux-kernel, linux-crypto
You're right. But I checked with checkpatch.pl and it reported:
WARNING: debugfs_remove_recursive(NULL) is safe and this check is
probably not required
#70: FILE: drivers/crypto/ccp/ccp-debugfs.c:324:
+ if (ccp_debugfs_dir) {
+ debugfs_remove_recursive(ccp_debugfs_dir);
Perhaps we could simplify it to:
mutex_lock(&ccp_debugfs_lock);
debugfs_remove_recursive(ccp_debugfs_dir);
ccp_debugfs_dir = NULL;
mutex_unlock(&ccp_debugfs_lock);
I'll send a v2 patch soon.
Tom Lendacky <thomas.lendacky@amd.com> 于2025年6月24日周二 01:17写道：
>
> On 6/23/25 01:25, Mengbiao Xiong wrote:
> > When CONFIG_CRYPTO_DEV_CCP_DEBUGFS is enabled, rebinding
> > the ccp device causes the following crash:
> >
> > $ echo '0000:0a:00.2' > /sys/bus/pci/drivers/ccp/unbind
> > $ echo '0000:0a:00.2' > /sys/bus/pci/drivers/ccp/bind
> >
> > [ 204.976930] BUG: kernel NULL pointer dereference, address: 0000000000000098
> > [ 204.978026] #PF: supervisor write access in kernel mode
> > [ 204.979126] #PF: error_code(0x0002) - not-present page
> > [ 204.980226] PGD 0 P4D 0
> > [ 204.981317] Oops: Oops: 0002 [#1] SMP NOPTI
> > ...
> > [ 204.997852] Call Trace:
> > [ 204.999074] <TASK>
> > [ 205.000297] start_creating+0x9f/0x1c0
> > [ 205.001533] debugfs_create_dir+0x1f/0x170
> > [ 205.002769] ? srso_return_thunk+0x5/0x5f
> > [ 205.004000] ccp5_debugfs_setup+0x87/0x170 [ccp]
> > [ 205.005241] ccp5_init+0x8b2/0x960 [ccp]
> > [ 205.006469] ccp_dev_init+0xd4/0x150 [ccp]
> > [ 205.007709] sp_init+0x5f/0x80 [ccp]
> > [ 205.008942] sp_pci_probe+0x283/0x2e0 [ccp]
> > [ 205.010165] ? srso_return_thunk+0x5/0x5f
> > [ 205.011376] local_pci_probe+0x4f/0xb0
> > [ 205.012584] pci_device_probe+0xdb/0x230
> > [ 205.013810] really_probe+0xed/0x380
> > [ 205.015024] __driver_probe_device+0x7e/0x160
> > [ 205.016240] device_driver_attach+0x2f/0x60
> > [ 205.017457] bind_store+0x7c/0xb0
> > [ 205.018663] drv_attr_store+0x28/0x40
> > [ 205.019868] sysfs_kf_write+0x5f/0x70
> > [ 205.021065] kernfs_fop_write_iter+0x145/0x1d0
> > [ 205.022267] vfs_write+0x308/0x440
> > [ 205.023453] ksys_write+0x6d/0xe0
> > [ 205.024616] __x64_sys_write+0x1e/0x30
> > [ 205.025778] x64_sys_call+0x16ba/0x2150
> > [ 205.026942] do_syscall_64+0x56/0x1e0
> > [ 205.028108] entry_SYSCALL_64_after_hwframe+0x76/0x7e
> > [ 205.029276] RIP: 0033:0x7fbc36f10104
> > [ 205.030420] Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 e1 08 2e 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5
> >
> > This patch sets ccp_debugfs_dir to NULL after destroying it in
> > ccp5_debugfs_destroy, allowing the directory dentry to be
> > recreated when rebinding the ccp device.
> >
> > Tested on AMD Ryzen 7 1700X.
> >
> > Fixes: 3cdbe346ed3f ("crypto: ccp - Add debugfs entries for CCP information")
> > Signed-off-by: Mengbiao Xiong <xisme1998@gmail.com>
> > ---
> > drivers/crypto/ccp/ccp-debugfs.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/crypto/ccp/ccp-debugfs.c b/drivers/crypto/ccp/ccp-debugfs.c
> > index a1055554b..0d432f3c4 100644
> > --- a/drivers/crypto/ccp/ccp-debugfs.c
> > +++ b/drivers/crypto/ccp/ccp-debugfs.c
> > @@ -320,4 +320,5 @@ void ccp5_debugfs_setup(struct ccp_device *ccp)
> > void ccp5_debugfs_destroy(void)
> > {
> > debugfs_remove_recursive(ccp_debugfs_dir);
> > + ccp_debugfs_dir = NULL;
>
> Hmmm... it seems like this should be protected by the mutex similar to how
> ccp5_debugfs_setup() is, right?
>
> Maybe something like:
>
> mutex_lock(&ccp_debugfs_lock);
> if (ccp_debugfs_dir) {
> debugfs_remove_recursive(ccp_debugfs_dir);
> ccp_debugfs_dir = NULL;
> }
> mutex_unlock(&ccp_debugfs_lock);
>
> That should also fix the issue, thoughts?
>
> Thanks,
> Tom
>
> > }
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-06-23 6:25 [PATCH] crypto: ccp - Fix crash when rebind ccp device for ccp.ko Mengbiao Xiong
2025-06-23 17:17 ` Tom Lendacky
2025-06-24 6:04 ` 1998 Xisme
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