Jan Kara cc1538c693 ext4: fix deadlock due to mbcache entry corruption ... commit a44e84a9b7 upstream. When manipulating xattr blocks, we can deadlock infinitely looping inside ext4_xattr_block_set() where we constantly keep finding xattr block for reuse in mbcache but we are unable to reuse it because its reference count is too big. This happens because cache entry for the xattr block is marked as reusable (e_reusable set) although its reference count is too big. When this inconsistency happens, this inconsistent state is kept indefinitely and so ext4_xattr_block_set() keeps retrying indefinitely. The inconsistent state is caused by non-atomic update of e_reusable bit. e_reusable is part of a bitfield and e_reusable update can race with update of e_referenced bit in the same bitfield resulting in loss of one of the updates. Fix the problem by using atomic bitops instead. This bug has been around for many years, but it became *much* easier to hit after commit 65f8b80053 ("ext4: fix race when reusing xattr blocks"). Cc: stable@vger.kernel.org Fixes: 6048c64b26 ("mbcache: add reusable flag to cache entries") Fixes: 65f8b80053 ("ext4: fix race when reusing xattr blocks") Reported-and-tested-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com> Reported-by: Thilo Fromm <t-lo@linux.microsoft.com> Link: https://lore.kernel.org/r/c77bf00f-4618-7149-56f1-b8d1664b9d07@linux.microsoft.com/ Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Andreas Dilger <adilger@dilger.ca> Link: https://lore.kernel.org/r/20221123193950.16758-1-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2023-01-07 11:12:02 +01:00
..
acpi	ACPI: APEI: Fix integer overflow in ghes_estatus_pool_init()	2022-10-13 20:40:09 +02:00
asm-generic	15 hotfixes. 11 marked cc:stable. Only three or four of the latter	2022-12-02 13:39:38 -08:00
clocksource
crypto
drm	drm/edid: add a quirk for two LG monitors to get them to work on 10bpc	2022-12-31 13:32:59 +01:00
dt-bindings	dt-bindings: clocks: imx8mp: Add ID for usb suspend clock	2022-12-31 13:33:09 +01:00
keys
kunit	kunit: declare kunit_assert structs as const	2022-10-07 10:19:18 -06:00
kvm
linux	ext4: fix deadlock due to mbcache entry corruption	2023-01-07 11:12:02 +01:00
math-emu
media	media: dvbdev: fix build warning due to comments	2022-12-31 13:33:12 +01:00
memory
misc
net	mptcp: remove MPTCP 'ifdef' in TCP SYN cookies	2023-01-07 11:11:44 +01:00
pcmcia
ras
rdma
rv
scsi	SCSI misc on 20221007	2022-10-07 12:33:18 -07:00
soc	ARM: at91: pm: avoid soft resetting AC DLL	2022-11-01 12:25:19 +02:00
sound	ALSA: hda/hdmi: fix stream-id config keep-alive for rt suspend	2022-12-31 13:33:07 +01:00
target
trace	ext4: disable fast-commit of encrypted dir operations	2023-01-07 11:12:00 +01:00
uapi	eventpoll: add EPOLL_URING_WAKE poll wakeup flag	2023-01-04 11:28:47 +01:00
ufs	SCSI misc on 20221007	2022-10-07 12:33:18 -07:00
vdso
video
xen	xen/virtio: enable grant based virtio on x86	2022-10-10 14:31:26 +02:00