Tetsuo Handa 53cb1e52c9 sysv: don't call sb_bread() with pointers_lock held ... [ Upstream commit f123dc8638 ] syzbot is reporting sleep in atomic context in SysV filesystem [1], for sb_bread() is called with rw_spinlock held. A "write_lock(&pointers_lock) => read_lock(&pointers_lock) deadlock" bug and a "sb_bread() with write_lock(&pointers_lock)" bug were introduced by "Replace BKL for chain locking with sysvfs-private rwlock" in Linux 2.5.12. Then, "[PATCH] err1-40: sysvfs locking fix" in Linux 2.6.8 fixed the former bug by moving pointers_lock lock to the callers, but instead introduced a "sb_bread() with read_lock(&pointers_lock)" bug (which made this problem easier to hit). Al Viro suggested that why not to do like get_branch()/get_block()/ find_shared() in Minix filesystem does. And doing like that is almost a revert of "[PATCH] err1-40: sysvfs locking fix" except that get_branch() from with find_shared() is called without write_lock(&pointers_lock). Reported-by: syzbot <syzbot+69b40dc5fd40f32c199f@syzkaller.appspotmail.com> Link: https://syzkaller.appspot.com/bug?extid=69b40dc5fd40f32c199f Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Link: https://lore.kernel.org/r/0d195f93-a22a-49a2-0020-103534d6f7f6@I-love.SAKURA.ne.jp Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2024-04-13 13:05:05 +02:00
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balloc.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
dir.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
file.c	fs: make helpers idmap mount aware	2021-01-24 14:27:20 +01:00
ialloc.c	inode: make init and permission helpers idmapped mount aware	2021-01-24 14:27:16 +01:00
inode.c	fs: allocate inode by using alloc_inode_sb()	2022-03-22 15:57:03 -07:00
itree.c	sysv: don't call sb_bread() with pointers_lock held	2024-04-13 13:05:05 +02:00
Kconfig	docs: filesystems: fix renamed references	2020-04-20 15:45:22 -06:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
namei.c	fs: make helpers idmap mount aware	2021-01-24 14:27:20 +01:00
super.c	fs: sysv: check sbi->s_firstdatazone in complete_read_super	2022-04-29 14:38:04 -07:00
sysv.h	fs: make helpers idmap mount aware	2021-01-24 14:27:20 +01:00