* [PATCH] scsi: sg: Avoid race in error handling & drop bogus warn
2024-03-29 14:37 ` Sachin Sant
@ 2024-04-01 9:56 ` Alexander Wetzel
2024-04-01 10:03 ` [PATCH v2] " Alexander Wetzel
2024-04-01 19:10 ` [PATCH v3] " Alexander Wetzel
2 siblings, 0 replies; 14+ messages in thread
From: Alexander Wetzel @ 2024-04-01 9:56 UTC (permalink / raw)
To: dgilbert
Cc: gregkh, sachinp, Alexander, bvanassche, linux-scsi, linuxppc-dev,
martin.petersen, stable
commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
introduced an incorrect WARN_ON_ONCE() and missed a sequence where
sg_device_destroy() after scsi_device_put() when handling errors.
sg_device_destroy() is accessing the parent scsi_device request_queue which
will already be set to NULL when the preceding call to scsi_device_put()
removed the last reference to the parent scsi_device.
Drop the incorrect WARN_ON_ONCE() - allowing more than one concurrent
access to the sg device - and make sure sg_device_destroy() is not used
after scsi_device_put() in the error handling.
Link: https://lore.kernel.org/all/5375B275-D137-4D5F-BE25-6AF8ACAE41EF@linux.ibm.com
Fixes: 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Wetzel <Alexander@wetzel-home.de>
---
The WARN_ON_ONCE() was kind of stupid to add:
We get add reference for each sg_open(). So opening a second session and
then closing either one will trigger the warning... Nothing to warn
about here.
Alexander
---
drivers/scsi/sg.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 386981c6976a..833c9277419b 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -372,8 +372,9 @@ sg_open(struct inode *inode, struct file *filp)
error_out:
scsi_autopm_put_device(sdp->device);
sdp_put:
+ kref_put(&sdp->d_ref, sg_device_destroy);
scsi_device_put(sdp->device);
- goto sg_put;
+ return retval;
}
/* Release resources associated with a successful sg_open()
@@ -2233,7 +2234,6 @@ sg_remove_sfp_usercontext(struct work_struct *work)
"sg_remove_sfp: sfp=0x%p\n", sfp));
kfree(sfp);
- WARN_ON_ONCE(kref_read(&sdp->d_ref) != 1);
kref_put(&sdp->d_ref, sg_device_destroy);
scsi_device_put(device);
module_put(THIS_MODULE);
--
2.44.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v2] scsi: sg: Avoid race in error handling & drop bogus warn
2024-03-29 14:37 ` Sachin Sant
2024-04-01 9:56 ` [PATCH] scsi: sg: Avoid race in error handling & drop bogus warn Alexander Wetzel
@ 2024-04-01 10:03 ` Alexander Wetzel
2024-04-01 17:09 ` Bart Van Assche
2024-04-01 19:10 ` [PATCH v3] " Alexander Wetzel
2 siblings, 1 reply; 14+ messages in thread
From: Alexander Wetzel @ 2024-04-01 10:03 UTC (permalink / raw)
To: dgilbert
Cc: gregkh, sachinp, Alexander, bvanassche, linux-scsi, linuxppc-dev,
martin.petersen, stable
commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
introduced an incorrect WARN_ON_ONCE() and missed a sequence where
sg_device_destroy() was used after scsi_device_put().
sg_device_destroy() is accessing the parent scsi_device request_queue which
will already be set to NULL when the preceding call to scsi_device_put()
removed the last reference to the parent scsi_device.
Drop the incorrect WARN_ON_ONCE() - allowing more than one concurrent
access to the sg device - and make sure sg_device_destroy() is not used
after scsi_device_put() in the error handling.
Link: https://lore.kernel.org/all/5375B275-D137-4D5F-BE25-6AF8ACAE41EF@linux.ibm.com
Fixes: 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Wetzel <Alexander@wetzel-home.de>
---
Changes compared to V1: fixed commit message
The WARN_ON_ONCE() was kind of stupid to add:
We get add reference for each sg_open(). So opening a second session and
then closing either one will trigger the warning... Nothing to warn
about here.
Alexander
---
drivers/scsi/sg.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 386981c6976a..833c9277419b 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -372,8 +372,9 @@ sg_open(struct inode *inode, struct file *filp)
error_out:
scsi_autopm_put_device(sdp->device);
sdp_put:
+ kref_put(&sdp->d_ref, sg_device_destroy);
scsi_device_put(sdp->device);
- goto sg_put;
+ return retval;
}
/* Release resources associated with a successful sg_open()
@@ -2233,7 +2234,6 @@ sg_remove_sfp_usercontext(struct work_struct *work)
"sg_remove_sfp: sfp=0x%p\n", sfp));
kfree(sfp);
- WARN_ON_ONCE(kref_read(&sdp->d_ref) != 1);
kref_put(&sdp->d_ref, sg_device_destroy);
scsi_device_put(device);
module_put(THIS_MODULE);
--
2.44.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* Re: [PATCH v2] scsi: sg: Avoid race in error handling & drop bogus warn
2024-04-01 10:03 ` [PATCH v2] " Alexander Wetzel
@ 2024-04-01 17:09 ` Bart Van Assche
2024-04-01 19:01 ` Alexander Wetzel
0 siblings, 1 reply; 14+ messages in thread
From: Bart Van Assche @ 2024-04-01 17:09 UTC (permalink / raw)
To: Alexander Wetzel, dgilbert
Cc: gregkh, sachinp, linux-scsi, linuxppc-dev, martin.petersen,
stable
On 4/1/24 03:03, Alexander Wetzel wrote:
> commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
> introduced an incorrect WARN_ON_ONCE() and missed a sequence where
> sg_device_destroy() was used after scsi_device_put().
Isn't that too negative? I think that the WARN_ON_ONCE() mentioned above
has proven to be useful: it helped to catch a bug.
> sg_device_destroy() is accessing the parent scsi_device request_queue which
> will already be set to NULL when the preceding call to scsi_device_put()
> removed the last reference to the parent scsi_device.
>
> Drop the incorrect WARN_ON_ONCE() - allowing more than one concurrent
> access to the sg device - and make sure sg_device_destroy() is not used
> after scsi_device_put() in the error handling.
>
> Link: https://lore.kernel.org/all/5375B275-D137-4D5F-BE25-6AF8ACAE41EF@linux.ibm.com
> Fixes: 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
The "goto sg_put" removed by this patch was introduced by commit
cc833acbee9d ("sg: O_EXCL and other lock handling"). Since the latter
commit is older than the one mentioned above, shouldn't the Fixes tag
refer to the latter commit?
> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
> index 386981c6976a..833c9277419b 100644
> --- a/drivers/scsi/sg.c
> +++ b/drivers/scsi/sg.c
> @@ -372,8 +372,9 @@ sg_open(struct inode *inode, struct file *filp)
> error_out:
> scsi_autopm_put_device(sdp->device);
> sdp_put:
> + kref_put(&sdp->d_ref, sg_device_destroy);
> scsi_device_put(sdp->device);
> - goto sg_put;
> + return retval;
> }
Please add a comment above "return retval" that explains which code will
drop the sg reference.
Thanks,
Bart.
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v2] scsi: sg: Avoid race in error handling & drop bogus warn
2024-04-01 17:09 ` Bart Van Assche
@ 2024-04-01 19:01 ` Alexander Wetzel
0 siblings, 0 replies; 14+ messages in thread
From: Alexander Wetzel @ 2024-04-01 19:01 UTC (permalink / raw)
To: Bart Van Assche, dgilbert
Cc: gregkh, sachinp, linux-scsi, linuxppc-dev, martin.petersen,
stable
On 01.04.24 19:09, Bart Van Assche wrote:
> On 4/1/24 03:03, Alexander Wetzel wrote:
>> commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
>> introduced an incorrect WARN_ON_ONCE() and missed a sequence where
>> sg_device_destroy() was used after scsi_device_put().
>
> Isn't that too negative? I think that the WARN_ON_ONCE() mentioned above
> has proven to be useful: it helped to catch a bug.
>
It helped to find the other issue. But the WARN_ON_ONCE() here is still
plain wrong. Any only explained by my lack of understanding of the code
and stupid assumptions I should have checked a bit more.
The warning always triggers when we have more than one user of the sg
device (and then free one of them).
While trying to understand the issue I tripped over the other wrong
sequence. Which is probably very seldom really executed...
That said I can of course update the wording when you have a better
suggestion. But I only have some variations of "Ups... sorry. I thought
that was a good idea. Turns out it's not"
>> sg_device_destroy() is accessing the parent scsi_device request_queue
>> which
>> will already be set to NULL when the preceding call to scsi_device_put()
>> removed the last reference to the parent scsi_device.
>>
>> Drop the incorrect WARN_ON_ONCE() - allowing more than one concurrent
>> access to the sg device - and make sure sg_device_destroy() is not used
>> after scsi_device_put() in the error handling.
>>
>> Link:
>> https://lore.kernel.org/all/5375B275-D137-4D5F-BE25-6AF8ACAE41EF@linux.ibm.com
>> Fixes: 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
>
> The "goto sg_put" removed by this patch was introduced by commit
> cc833acbee9d ("sg: O_EXCL and other lock handling"). Since the latter
> commit is older than the one mentioned above, shouldn't the Fixes tag
> refer to the latter commit?
>
The order was not wrong till commit db59133e9279 ("scsi: sg: fix
blktrace debugfs entries leakage"), the one my original patch tried to
fix. Prior to that one sg_device_destroy() was not using the scsi device
request_queue.
I guess I (or one maintainer) could add that commit here again, too...
My reasoning here is, that this patch here fixes what my first patch got
wrong.
Which is already heading into the stable trees. And I would prefer to
not have any kernel release with commit 27f58c04a8f4 ("scsi: sg: Avoid
sg device teardown race") without this fix, too.
>> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
>> index 386981c6976a..833c9277419b 100644
>> --- a/drivers/scsi/sg.c
>> +++ b/drivers/scsi/sg.c
>> @@ -372,8 +372,9 @@ sg_open(struct inode *inode, struct file *filp)
>> error_out:
>> scsi_autopm_put_device(sdp->device);
>> sdp_put:
>> + kref_put(&sdp->d_ref, sg_device_destroy);
>> scsi_device_put(sdp->device);
>> - goto sg_put;
>> + return retval;
>> }
>
> Please add a comment above "return retval" that explains which code will
> drop the sg reference.
>
Hm, don't get that. That kref_put() is the one dropping the reference.
The matching kref_get() is in sg_add_sfp(). Which is called a few lines
prior to the code here (line 350).
The patch is literally only swapping the order of scsi_device_put() and
kref_put().
Which *again* causes a use-after free. So I'll send out v3 immediately
and if any of the thinks discussed here require a v4 we'll do that.
Alexander
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH v3] scsi: sg: Avoid race in error handling & drop bogus warn
2024-03-29 14:37 ` Sachin Sant
2024-04-01 9:56 ` [PATCH] scsi: sg: Avoid race in error handling & drop bogus warn Alexander Wetzel
2024-04-01 10:03 ` [PATCH v2] " Alexander Wetzel
@ 2024-04-01 19:10 ` Alexander Wetzel
2024-04-02 6:01 ` Sachin Sant
` (4 more replies)
2 siblings, 5 replies; 14+ messages in thread
From: Alexander Wetzel @ 2024-04-01 19:10 UTC (permalink / raw)
To: dgilbert
Cc: gregkh, sachinp, Alexander, bvanassche, linux-scsi, linuxppc-dev,
martin.petersen, stable
commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
introduced an incorrect WARN_ON_ONCE() and missed a sequence where
sg_device_destroy() was used after scsi_device_put().
sg_device_destroy() is accessing the parent scsi_device request_queue which
will already be set to NULL when the preceding call to scsi_device_put()
removed the last reference to the parent scsi_device.
Drop the incorrect WARN_ON_ONCE() - allowing more than one concurrent
access to the sg device - and make sure sg_device_destroy() is not used
after scsi_device_put() in the error handling.
Link: https://lore.kernel.org/all/5375B275-D137-4D5F-BE25-6AF8ACAE41EF@linux.ibm.com
Fixes: 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Wetzel <Alexander@wetzel-home.de>
---
Changes compared to V1: fixed commit message
Changes compared to V2: Fix use-after free
---
drivers/scsi/sg.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 386981c6976a..baf870a03ecf 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -285,6 +285,7 @@ sg_open(struct inode *inode, struct file *filp)
int dev = iminor(inode);
int flags = filp->f_flags;
struct request_queue *q;
+ struct scsi_device *device;
Sg_device *sdp;
Sg_fd *sfp;
int retval;
@@ -301,11 +302,12 @@ sg_open(struct inode *inode, struct file *filp)
/* This driver's module count bumped by fops_get in <linux/fs.h> */
/* Prevent the device driver from vanishing while we sleep */
- retval = scsi_device_get(sdp->device);
+ device = sdp->device;
+ retval = scsi_device_get(device);
if (retval)
goto sg_put;
- retval = scsi_autopm_get_device(sdp->device);
+ retval = scsi_autopm_get_device(device);
if (retval)
goto sdp_put;
@@ -313,7 +315,7 @@ sg_open(struct inode *inode, struct file *filp)
* check if O_NONBLOCK. Permits SCSI commands to be issued
* during error recovery. Tread carefully. */
if (!((flags & O_NONBLOCK) ||
- scsi_block_when_processing_errors(sdp->device))) {
+ scsi_block_when_processing_errors(device))) {
retval = -ENXIO;
/* we are in error recovery for this device */
goto error_out;
@@ -344,7 +346,7 @@ sg_open(struct inode *inode, struct file *filp)
if (sdp->open_cnt < 1) { /* no existing opens */
sdp->sgdebug = 0;
- q = sdp->device->request_queue;
+ q = device->request_queue;
sdp->sg_tablesize = queue_max_segments(q);
}
sfp = sg_add_sfp(sdp);
@@ -370,10 +372,11 @@ sg_open(struct inode *inode, struct file *filp)
error_mutex_locked:
mutex_unlock(&sdp->open_rel_lock);
error_out:
- scsi_autopm_put_device(sdp->device);
+ scsi_autopm_put_device(device);
sdp_put:
- scsi_device_put(sdp->device);
- goto sg_put;
+ kref_put(&sdp->d_ref, sg_device_destroy);
+ scsi_device_put(device);
+ return retval;
}
/* Release resources associated with a successful sg_open()
@@ -2233,7 +2236,6 @@ sg_remove_sfp_usercontext(struct work_struct *work)
"sg_remove_sfp: sfp=0x%p\n", sfp));
kfree(sfp);
- WARN_ON_ONCE(kref_read(&sdp->d_ref) != 1);
kref_put(&sdp->d_ref, sg_device_destroy);
scsi_device_put(device);
module_put(THIS_MODULE);
--
2.44.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* Re: [PATCH v3] scsi: sg: Avoid race in error handling & drop bogus warn
2024-04-01 19:10 ` [PATCH v3] " Alexander Wetzel
@ 2024-04-02 6:01 ` Sachin Sant
2024-04-03 23:24 ` Bart Van Assche
` (3 subsequent siblings)
4 siblings, 0 replies; 14+ messages in thread
From: Sachin Sant @ 2024-04-02 6:01 UTC (permalink / raw)
To: Alexander Wetzel
Cc: dgilbert, gregkh, Bart Van Assche, linux-scsi, linuxppc-dev,
Martin K . Petersen, stable
> On 2 Apr 2024, at 12:40 AM, Alexander Wetzel <Alexander@wetzel-home.de> wrote:
>
> commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
> introduced an incorrect WARN_ON_ONCE() and missed a sequence where
> sg_device_destroy() was used after scsi_device_put().
>
> sg_device_destroy() is accessing the parent scsi_device request_queue which
> will already be set to NULL when the preceding call to scsi_device_put()
> removed the last reference to the parent scsi_device.
>
> Drop the incorrect WARN_ON_ONCE() - allowing more than one concurrent
> access to the sg device - and make sure sg_device_destroy() is not used
> after scsi_device_put() in the error handling.
>
> Link: https://lore.kernel.org/all/5375B275-D137-4D5F-BE25-6AF8ACAE41EF@linux.ibm.com
> Fixes: 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
> Cc: stable@vger.kernel.org
> Signed-off-by: Alexander Wetzel <Alexander@wetzel-home.de>
> ---
Thanks for the fix. I tested this patch and confirm it fixes the reported problem.
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
— Sachin
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v3] scsi: sg: Avoid race in error handling & drop bogus warn
2024-04-01 19:10 ` [PATCH v3] " Alexander Wetzel
2024-04-02 6:01 ` Sachin Sant
@ 2024-04-03 23:24 ` Bart Van Assche
2024-04-04 6:55 ` Alexander Wetzel
2024-04-04 16:34 ` Bart Van Assche
` (2 subsequent siblings)
4 siblings, 1 reply; 14+ messages in thread
From: Bart Van Assche @ 2024-04-03 23:24 UTC (permalink / raw)
To: Alexander Wetzel, dgilbert
Cc: gregkh, sachinp, linux-scsi, linuxppc-dev, martin.petersen,
stable
On 4/1/24 12:10 PM, Alexander Wetzel wrote:
> @@ -301,11 +302,12 @@ sg_open(struct inode *inode, struct file *filp)
>
> /* This driver's module count bumped by fops_get in <linux/fs.h> */
> /* Prevent the device driver from vanishing while we sleep */
> - retval = scsi_device_get(sdp->device);
> + device = sdp->device;
> + retval = scsi_device_get(device);
> if (retval)
> goto sg_put;
Are all the sdp->device -> device changes essential? Isn't there a
preference to minimize patches that will end up in the stable trees?
Thanks,
Bart.
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v3] scsi: sg: Avoid race in error handling & drop bogus warn
2024-04-03 23:24 ` Bart Van Assche
@ 2024-04-04 6:55 ` Alexander Wetzel
0 siblings, 0 replies; 14+ messages in thread
From: Alexander Wetzel @ 2024-04-04 6:55 UTC (permalink / raw)
To: Bart Van Assche, dgilbert
Cc: gregkh, sachinp, linux-scsi, linuxppc-dev, martin.petersen,
stable
On 04.04.24 01:24, Bart Van Assche wrote:
> On 4/1/24 12:10 PM, Alexander Wetzel wrote:
>> @@ -301,11 +302,12 @@ sg_open(struct inode *inode, struct file *filp)
>> /* This driver's module count bumped by fops_get in <linux/fs.h> */
>> /* Prevent the device driver from vanishing while we sleep */
>> - retval = scsi_device_get(sdp->device);
>> + device = sdp->device;
>> + retval = scsi_device_get(device);
>> if (retval)
>> goto sg_put;
>
> Are all the sdp->device -> device changes essential? Isn't there a
> preference to minimize patches that will end up in the stable trees?
>
Only the very last change is essential:
- scsi_device_put(sdp->device);
- goto sg_put;
+ kref_put(&sdp->d_ref, sg_device_destroy);
+ scsi_device_put(device);
+ return retval;
Not using a (required) local variable and de-referencing it again and
looks strange for anyone reading the code. While the additional lines in
the patch are trivial to review...
Alexander
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v3] scsi: sg: Avoid race in error handling & drop bogus warn
2024-04-01 19:10 ` [PATCH v3] " Alexander Wetzel
2024-04-02 6:01 ` Sachin Sant
2024-04-03 23:24 ` Bart Van Assche
@ 2024-04-04 16:34 ` Bart Van Assche
2024-04-04 22:22 ` Martin K. Petersen
2024-04-06 1:58 ` Martin K. Petersen
4 siblings, 0 replies; 14+ messages in thread
From: Bart Van Assche @ 2024-04-04 16:34 UTC (permalink / raw)
To: Alexander Wetzel, dgilbert
Cc: gregkh, sachinp, linux-scsi, linuxppc-dev, martin.petersen,
stable
On 4/1/24 12:10, Alexander Wetzel wrote:
> commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
> introduced an incorrect WARN_ON_ONCE() and missed a sequence where
> sg_device_destroy() was used after scsi_device_put().
>
> sg_device_destroy() is accessing the parent scsi_device request_queue which
> will already be set to NULL when the preceding call to scsi_device_put()
> removed the last reference to the parent scsi_device.
>
> Drop the incorrect WARN_ON_ONCE() - allowing more than one concurrent
> access to the sg device - and make sure sg_device_destroy() is not used
> after scsi_device_put() in the error handling.
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v3] scsi: sg: Avoid race in error handling & drop bogus warn
2024-04-01 19:10 ` [PATCH v3] " Alexander Wetzel
` (2 preceding siblings ...)
2024-04-04 16:34 ` Bart Van Assche
@ 2024-04-04 22:22 ` Martin K. Petersen
2024-04-06 1:58 ` Martin K. Petersen
4 siblings, 0 replies; 14+ messages in thread
From: Martin K. Petersen @ 2024-04-04 22:22 UTC (permalink / raw)
To: Alexander Wetzel
Cc: dgilbert, gregkh, sachinp, bvanassche, linux-scsi, linuxppc-dev,
martin.petersen, stable
Alexander,
> commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
> introduced an incorrect WARN_ON_ONCE() and missed a sequence where
> sg_device_destroy() was used after scsi_device_put().
Applied to 6.9/scsi-fixes, thanks!
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v3] scsi: sg: Avoid race in error handling & drop bogus warn
2024-04-01 19:10 ` [PATCH v3] " Alexander Wetzel
` (3 preceding siblings ...)
2024-04-04 22:22 ` Martin K. Petersen
@ 2024-04-06 1:58 ` Martin K. Petersen
4 siblings, 0 replies; 14+ messages in thread
From: Martin K. Petersen @ 2024-04-06 1:58 UTC (permalink / raw)
To: dgilbert, Alexander Wetzel
Cc: Martin K . Petersen, gregkh, sachinp, bvanassche, linux-scsi,
linuxppc-dev, stable
On Mon, 01 Apr 2024 21:10:38 +0200, Alexander Wetzel wrote:
> commit 27f58c04a8f4 ("scsi: sg: Avoid sg device teardown race")
> introduced an incorrect WARN_ON_ONCE() and missed a sequence where
> sg_device_destroy() was used after scsi_device_put().
>
> sg_device_destroy() is accessing the parent scsi_device request_queue which
> will already be set to NULL when the preceding call to scsi_device_put()
> removed the last reference to the parent scsi_device.
>
> [...]
Applied to 6.9/scsi-fixes, thanks!
[1/1] scsi: sg: Avoid race in error handling & drop bogus warn
https://git.kernel.org/mkp/scsi/c/d4e655c49f47
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 14+ messages in thread