4.20-stable review patch. If anyone has any objections, please let me know.
------------------
From: Minchan Kim <minchan@xxxxxxxxxx>
commit 5547932dc67a48713eece4fa4703bfdf0cfcb818 upstream.
If blkdev_get fails, we shouldn't do blkdev_put. Otherwise, kernel emits
below log. This patch fixes it.
WARNING: CPU: 0 PID: 1893 at fs/block_dev.c:1828 blkdev_put+0x105/0x120
Modules linked in:
CPU: 0 PID: 1893 Comm: swapoff Not tainted 4.19.0+ #453
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
RIP: 0010:blkdev_put+0x105/0x120
Call Trace:
__x64_sys_swapoff+0x46d/0x490
do_syscall_64+0x5a/0x190
entry_SYSCALL_64_after_hwframe+0x49/0xbe
irq event stamp: 4466
hardirqs last enabled at (4465): __free_pages_ok+0x1e3/0x490
hardirqs last disabled at (4466): trace_hardirqs_off_thunk+0x1a/0x1c
softirqs last enabled at (3420): __do_softirq+0x333/0x446
softirqs last disabled at (3407): irq_exit+0xd1/0xe0
Link: http://lkml.kernel.org/r/20181127055429.251614-3-minchan@xxxxxxxxxx
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Reviewed-by: Joey Pabalinas <joeypabalinas@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [4.14+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -382,8 +382,10 @@ static ssize_t backing_dev_store(struct
bdev = bdgrab(I_BDEV(inode));
err = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram);
- if (err < 0)
+ if (err < 0) {
+ bdev = NULL;
goto out;
+ }
nr_pages = i_size_read(inode) >> PAGE_SHIFT;
bitmap_sz = BITS_TO_LONGS(nr_pages) * sizeof(long);
