6.6-stable review patch. If anyone has any objections, please let me know.
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From: Alexander Wetzel Alexander@wetzel-home.de
[ Upstream commit 27f58c04a8f438078583041468ec60597841284d ]
sg_remove_sfp_usercontext() must not use sg_device_destroy() after calling 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.
The resulting NULL pointer exception will then crash the kernel.
Link: https://lore.kernel.org/r/20240305150509.23896-1-Alexander@wetzel-home.de Fixes: db59133e9279 ("scsi: sg: fix blktrace debugfs entries leakage") Cc: stable@vger.kernel.org Signed-off-by: Alexander Wetzel Alexander@wetzel-home.de Link: https://lore.kernel.org/r/20240320213032.18221-1-Alexander@wetzel-home.de Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/sg.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 0d8afffd1683b..8bd95ee1825a6 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -2208,6 +2208,7 @@ sg_remove_sfp_usercontext(struct work_struct *work) { struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work); struct sg_device *sdp = sfp->parentdp; + struct scsi_device *device = sdp->device; Sg_request *srp; unsigned long iflags;
@@ -2233,8 +2234,9 @@ sg_remove_sfp_usercontext(struct work_struct *work) "sg_remove_sfp: sfp=0x%p\n", sfp)); kfree(sfp);
- scsi_device_put(sdp->device); + 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); }