Chao Yu a949dc5f2c f2fs: compress: fix race condition of overwrite vs truncate ... pos_fsstress testcase complains a panic as belew: ------------[ cut here ]------------ kernel BUG at fs/f2fs/compress.c:1082! invalid opcode: 0000 [#1] SMP PTI CPU: 4 PID: 2753477 Comm: kworker/u16:2 Tainted: G OE 5.12.0-rc1-custom #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Workqueue: writeback wb_workfn (flush-252:16) RIP: 0010:prepare_compress_overwrite+0x4c0/0x760 [f2fs] Call Trace: f2fs_prepare_compress_overwrite+0x5f/0x80 [f2fs] f2fs_write_cache_pages+0x468/0x8a0 [f2fs] f2fs_write_data_pages+0x2a4/0x2f0 [f2fs] do_writepages+0x38/0xc0 __writeback_single_inode+0x44/0x2a0 writeback_sb_inodes+0x223/0x4d0 __writeback_inodes_wb+0x56/0xf0 wb_writeback+0x1dd/0x290 wb_workfn+0x309/0x500 process_one_work+0x220/0x3c0 worker_thread+0x53/0x420 kthread+0x12f/0x150 ret_from_fork+0x22/0x30 The root cause is truncate() may race with overwrite as below, so that one reference count left in page can not guarantee the page attaching in mapping tree all the time, after truncation, later find_lock_page() may return NULL pointer. - prepare_compress_overwrite - f2fs_pagecache_get_page - unlock_page - f2fs_setattr - truncate_setsize - truncate_inode_page - delete_from_page_cache - find_lock_page Fix this by avoiding referencing updated page. Fixes: 4c8ff7095b ("f2fs: support data compression") Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>		2021-05-11 14:48:12 -07:00
..
acl.c	f2fs: clean up build warnings	2021-04-10 10:36:39 -07:00
acl.h	fs: make helpers idmap mount aware	2021-01-24 14:27:20 +01:00
checkpoint.c	f2fs-for-5.13-rc1	2021-05-04 18:03:38 -07:00
compress.c	f2fs: compress: fix race condition of overwrite vs truncate	2021-05-11 14:48:12 -07:00
data.c	f2fs-for-5.13-rc1	2021-05-04 18:03:38 -07:00
debug.c	f2fs: clean up build warnings	2021-04-10 10:36:39 -07:00
dir.c	f2fs-for-5.13-rc1	2021-05-04 18:03:38 -07:00
extent_cache.c	f2fs: support 64-bits key in f2fs rb-tree node entry	2020-09-10 14:03:30 -07:00
f2fs.h	f2fs-for-5.13-rc1	2021-05-04 18:03:38 -07:00
file.c	f2fs: support iflag change given the mask	2021-05-11 14:48:11 -07:00
gc.c	f2fs: clean up build warnings	2021-04-10 10:36:39 -07:00
gc.h	f2fs: introduce gc_merge mount option	2021-03-30 18:48:56 -07:00
hash.c	f2fs: Handle casefolding with Encryption	2020-12-02 22:00:21 -08:00
inline.c	f2fs: fix a redundant call to f2fs_balance_fs if an error occurs	2021-03-12 13:16:44 -08:00
inode.c	f2fs: clean up build warnings	2021-04-10 10:36:39 -07:00
Kconfig	f2fs: compress: Allow modular (de)compression algorithms	2021-03-12 13:16:42 -08:00
Makefile	f2fs: deprecate f2fs_trace_io	2021-01-27 15:20:07 -08:00
namei.c	f2fs-for-5.13-rc1	2021-05-04 18:03:38 -07:00
node.c	f2fs: clean up build warnings	2021-04-10 10:36:39 -07:00
node.h	f2fs: allow to change discard policy based on cached discard cmds	2021-03-26 10:27:44 -07:00
recovery.c	f2fs: clean up build warnings	2021-04-10 10:36:39 -07:00
segment.c	f2fs: avoid null pointer access when handling IPU error	2021-05-11 14:48:07 -07:00
segment.h	f2fs-for-5.13-rc1	2021-05-04 18:03:38 -07:00
shrinker.c	f2fs: avoid race condition for shrinker count	2020-12-03 00:59:26 -08:00
super.c	f2fs-for-5.13-rc1	2021-05-04 18:03:38 -07:00
sysfs.c	f2fs: add sysfs nodes to get runtime compression stat	2021-03-25 18:20:50 -07:00
verity.c	f2fs-for-5.13-rc1	2021-05-04 18:03:38 -07:00
xattr.c	f2fs: clean up build warnings	2021-04-10 10:36:39 -07:00
xattr.h	f2fs: code cleanup by removing ifdef macro surrounding	2020-05-26 18:56:10 -07:00