block,scsi: verify return pointer from blk_get_request
The blk-core dead queue checks introduce an error scenario to
blk_get_request that returns NULL if the request queue has been
shutdown. This affects the behavior for __GFP_WAIT callers, who should
verify the return value before dereferencing.
Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 51bf515..29d0567 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -448,6 +448,10 @@
}
rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);
+ if (!rq) {
+ err = -ENODEV;
+ goto error_free_buffer;
+ }
cmdlen = COMMAND_SIZE(opcode);
@@ -520,8 +524,9 @@
}
error:
- kfree(buffer);
blk_put_request(rq);
+error_free_buffer:
+ kfree(buffer);
return err;
}
EXPORT_SYMBOL_GPL(sg_scsi_ioctl);
@@ -534,6 +539,8 @@
int err;
rq = blk_get_request(q, WRITE, __GFP_WAIT);
+ if (!rq)
+ return -ENODEV;
blk_rq_set_block_pc(rq);
rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
rq->cmd[0] = cmd;
