blob: 90b271dc4ac166e11781ccdce4472be834e20ad4 [file] [log] [blame]
From 8ee90b6672bc74150b719ebbed9822ae38c4b927 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Wed, 9 Oct 2019 10:35:36 -0700
Subject: [PATCH] scsi: ch: Make it possible to open a ch device multiple times
again
commit 6a0990eaa768dfb7064f06777743acc6d392084b upstream.
Clearing ch->device in ch_release() is wrong because that pointer must
remain valid until ch_remove() is called. This patch fixes the following
crash the second time a ch device is opened:
BUG: kernel NULL pointer dereference, address: 0000000000000790
RIP: 0010:scsi_device_get+0x5/0x60
Call Trace:
ch_open+0x4c/0xa0 [ch]
chrdev_open+0xa2/0x1c0
do_dentry_open+0x13a/0x380
path_openat+0x591/0x1470
do_filp_open+0x91/0x100
do_sys_open+0x184/0x220
do_syscall_64+0x5f/0x1a0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: 085e56766f74 ("scsi: ch: add refcounting")
Cc: Hannes Reinecke <hare@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191009173536.247889-1-bvanassche@acm.org
Reported-by: Rob Turk <robtu@rtist.nl>
Suggested-by: Rob Turk <robtu@rtist.nl>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index 5f8153c37f77..76751d6c7f0d 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -579,7 +579,6 @@ ch_release(struct inode *inode, struct file *file)
scsi_changer *ch = file->private_data;
scsi_device_put(ch->device);
- ch->device = NULL;
file->private_data = NULL;
kref_put(&ch->ref, ch_destroy);
return 0;
--
2.7.4