[PATCH v4] scsi: mpi3mr: fix possible crash when setup bsg fail

Guixin Liu
2025-01-07T02:20:45Z

If bsg_setup_queue() fails, the bsg_queue is assigned a non-NULL value.
Consequently, in mpi3mr_bsg_exit(), the condition
"if(!mrioc->bsg_queue)" will not be satisfied, preventing execution
from entering bsg_remove_queue(), which could lead to the following
crash:

BUG: kernel NULL pointer dereference, address: 000000000000041c
Call Trace:
<TASK>
mpi3mr_bsg_exit+0x1f/0x50 [mpi3mr]
mpi3mr_remove+0x6f/0x340 [mpi3mr]
pci_device_remove+0x3f/0xb0
device_release_driver_internal+0x19d/0x220
unbind_store+0xa4/0xb0
kernfs_fop_write_iter+0x11f/0x200
vfs_write+0x1fc/0x3e0
ksys_write+0x67/0xe0
do_syscall_64+0x38/0x80
entry_SYSCALL_64_after_hwframe+0x78/0xe2

Fixes: 4268fa751365 ("scsi: mpi3mr: Add bsg device support")
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
---
Changes from v3 to v4:
- Clean up the call trace (Bart).
- Add the rb tag from Bart, thanks.

Changes from v2 to v3:
- Add the crash stack to commit body.

Changes from v1 to v2:
- Add return statement when setup bsg queue fail, sorry for the v1
trouble.
drivers/scsi/mpi3mr/mpi3mr_app.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/mpi3mr/mpi3mr_app.c b/drivers/scsi/mpi3mr/mpi3mr_app.c
index 10b8e4dc64f8..7589f48aebc8 100644
--- a/drivers/scsi/mpi3mr/mpi3mr_app.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_app.c
@@ -2951,6 +2951,7 @@ void mpi3mr_bsg_init(struct mpi3mr_ioc *mrioc)
.max_hw_sectors = MPI3MR_MAX_APP_XFER_SECTORS,
.max_segments = MPI3MR_MAX_APP_XFER_SEGMENTS,
};
+ struct request_queue *q;

device_initialize(bsg_dev);

@@ -2966,14 +2967,17 @@ void mpi3mr_bsg_init(struct mpi3mr_ioc *mrioc)
return;
}

- mrioc->bsg_queue = bsg_setup_queue(bsg_dev, dev_name(bsg_dev), &lim,
+ q = bsg_setup_queue(bsg_dev, dev_name(bsg_dev), &lim,
mpi3mr_bsg_request, NULL, 0);
- if (IS_ERR(mrioc->bsg_queue)) {
+ if (IS_ERR(q)) {
ioc_err(mrioc, "%s: bsg registration failed\n",
dev_name(bsg_dev));
device_del(bsg_dev);
put_device(bsg_dev);
+ return;
}
+
+ mrioc->bsg_queue = q;
}

/**
--
2.43.0