https://github.com/torvalds/linux
Revision ec084de929e419e51bcdafaafe567d9e7d0273b7 authored by Jiufei Xue on 17 May 2019, 21:31:44 UTC, committed by Linus Torvalds on 18 May 2019, 22:52:26 UTC
synchronize_rcu() didn't wait for call_rcu() callbacks, so inode wb
switch may not go to the workqueue after synchronize_rcu(). Thus
previous scheduled switches was not finished even flushing the
workqueue, which will cause a NULL pointer dereferenced followed below.
VFS: Busy inodes after unmount of vdd. Self-destruct in 5 seconds. Have a nice day...
BUG: unable to handle kernel NULL pointer dereference at 0000000000000278
evict+0xb3/0x180
iput+0x1b0/0x230
inode_switch_wbs_work_fn+0x3c0/0x6a0
worker_thread+0x4e/0x490
? process_one_work+0x410/0x410
kthread+0xe6/0x100
ret_from_fork+0x39/0x50
Replace the synchronize_rcu() call with a rcu_barrier() to wait for all
pending callbacks to finish. And inc isw_nr_in_flight after call_rcu()
in inode_switch_wbs() to make more sense.
Link: http://lkml.kernel.org/r/20190429024108.54150-1-jiufei.xue@linux.alibaba.com
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Acked-by: Tejun Heo <tj@kernel.org>
Suggested-by: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 60fce36
Tip revision: ec084de929e419e51bcdafaafe567d9e7d0273b7 authored by Jiufei Xue on 17 May 2019, 21:31:44 UTC
fs/writeback.c: use rcu_barrier() to wait for inflight wb switches going into workqueue when umount
fs/writeback.c: use rcu_barrier() to wait for inflight wb switches going into workqueue when umount
Tip revision: ec084de
| File | Mode | Size |
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | -rw-r--r-- | 14.6 KB |
| .cocciconfig | -rw-r--r-- | 59 bytes |
| .get_maintainer.ignore | -rw-r--r-- | 31 bytes |
| .gitattributes | -rw-r--r-- | 30 bytes |
| .gitignore | -rw-r--r-- | 1.6 KB |
| .mailmap | -rw-r--r-- | 11.9 KB |
| COPYING | -rw-r--r-- | 423 bytes |
| CREDITS | -rw-r--r-- | 96.9 KB |
| Kbuild | -rw-r--r-- | 1.5 KB |
| Kconfig | -rw-r--r-- | 563 bytes |
| MAINTAINERS | -rw-r--r-- | 498.8 KB |
| Makefile | -rw-r--r-- | 59.0 KB |
| README | -rw-r--r-- | 727 bytes |
Computing file changes ...
