kernel.git/fs/ext4/super.c, branch linux-5.12.y

ext4: fix WARN_ON_ONCE(!buffer_uptodate) after an error writing the superblock

2021-07-20T14:02:16Z

[ Upstream commit 558d6450c7755aa005d89021204b6cdcae5e848f ] If a writeback of the superblock fails with an I/O error, the buffer is marked not uptodate. However, this can cause a WARN_ON to trigger when we attempt to write superblock a second time. (Which might succeed this time, for cerrtain types of block devices such as iSCSI devices over a flaky network.) Try to detect this case in flush_stashed_error_work(), and also change __ext4_handle_dirty_metadata() so we always set the uptodate flag, not just in the nojournal case. Before this commit, this problem can be repliciated via: 1. dmsetup create dust1 --table '0 2097152 dust /dev/sdc 0 4096' 2. mount /dev/mapper/dust1 /home/test 3. dmsetup message dust1 0 addbadblock 0 10 4. cd /home/test 5. echo "XXXXXXX" > t After a few seconds, we got following warning: [ 80.654487] end_buffer_async_write: bh=0xffff88842f18bdd0 [ 80.656134] Buffer I/O error on dev dm-0, logical block 0, lost async page write [ 85.774450] EXT4-fs error (device dm-0): ext4_check_bdev_write_error:193: comm kworker/u16:8: Error while async write back metadata [ 91.415513] mark_buffer_dirty: bh=0xffff88842f18bdd0 [ 91.417038] ------------[ cut here ]------------ [ 91.418450] WARNING: CPU: 1 PID: 1944 at fs/buffer.c:1092 mark_buffer_dirty.cold+0x1c/0x5e [ 91.440322] Call Trace: [ 91.440652] __jbd2_journal_temp_unlink_buffer+0x135/0x220 [ 91.441354] __jbd2_journal_unfile_buffer+0x24/0x90 [ 91.441981] __jbd2_journal_refile_buffer+0x134/0x1d0 [ 91.442628] jbd2_journal_commit_transaction+0x249a/0x3240 [ 91.443336] ? put_prev_entity+0x2a/0x200 [ 91.443856] ? kjournald2+0x12e/0x510 [ 91.444324] kjournald2+0x12e/0x510 [ 91.444773] ? woken_wake_function+0x30/0x30 [ 91.445326] kthread+0x150/0x1b0 [ 91.445739] ? commit_timeout+0x20/0x20 [ 91.446258] ? kthread_flush_worker+0xb0/0xb0 [ 91.446818] ret_from_fork+0x1f/0x30 [ 91.447293] ---[ end trace 66f0b6bf3d1abade ]--- Signed-off-by: Ye Bin Link: https://lore.kernel.org/r/20210615090537.3423231-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix memory leak in ext4_fill_super

2021-07-19T08:01:28Z

commit 618f003199c6188e01472b03cdbba227f1dc5f24 upstream. static int kthread(void *_create) will return -ENOMEM or -EINTR in case of internal failure or kthread_stop() call happens before threadfn call. To prevent fancy error checking and make code more straightforward we moved all cleanup code out of kmmpd threadfn. Also, dropped struct mmpd_data at all. Now struct super_block is a threadfn data and struct buffer_head embedded into struct ext4_sb_info. Reported-by: syzbot+d9e482e303930fa4f6ff@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Link: https://lore.kernel.org/r/20210430185046.15742-1-paskripkin@gmail.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: return error code when ext4_fill_flex_info() fails

2021-07-14T14:59:06Z

commit 8f6840c4fd1e7bd715e403074fb161c1a04cda73 upstream. After commit c89128a00838 ("ext4: handle errors on ext4_commit_super"), 'ret' may be set to 0 before calling ext4_fill_flex_info(), if ext4_fill_flex_info() fails ext4_mount() doesn't return error code, it makes 'root' is null which causes crash in legacy_get_tree(). Fixes: c89128a00838 ("ext4: handle errors on ext4_commit_super") Reported-by: Hulk Robot Cc: # v4.18+ Signed-off-by: Yang Yingliang Link: https://lore.kernel.org/r/20210510111051.55650-1-yangyingliang@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: cleanup in-core orphan list if ext4_truncate() failed to get a transaction handle

2021-07-14T14:59:05Z

commit b9a037b7f3c401d3c63e0423e56aef606b1ffaaf upstream. In ext4_orphan_cleanup(), if ext4_truncate() failed to get a transaction handle, it didn't remove the inode from the in-core orphan list, which may probably trigger below error dump in ext4_destroy_inode() during the final iput() and could lead to memory corruption on the later orphan list changes. EXT4-fs (sda): Inode 6291467 (00000000b8247c67): orphan list check failed! 00000000b8247c67: 0001f30a 00000004 00000000 00000023 ............#... 00000000e24cde71: 00000006 014082a3 00000000 00000000 ......@......... 0000000072c6a5ee: 00000000 00000000 00000000 00000000 ................ ... This patch fix this by cleanup in-core orphan list manually if ext4_truncate() return error. Cc: stable@kernel.org Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20210507071904.160808-1-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: fix memory leak in ext4_fill_super

2021-06-10T11:41:44Z

commit afd09b617db3786b6ef3dc43e28fe728cfea84df upstream. Buffer head references must be released before calling kill_bdev(); otherwise the buffer head (and its page referenced by b_data) will not be freed by kill_bdev, and subsequently that bh will be leaked. If blocksizes differ, sb_set_blocksize() will kill current buffers and page cache by using kill_bdev(). And then super block will be reread again but using correct blocksize this time. sb_set_blocksize() didn't fully free superblock page and buffer head, and being busy, they were not freed and instead leaked. This can easily be reproduced by calling an infinite loop of: systemctl start .mount, and systemctl stop .mount ... since systemd creates a cgroup for each slice which it mounts, and the bh leak get amplified by a dying memory cgroup that also never gets freed, and memory consumption is much more easily noticed. Fixes: ce40733ce93d ("ext4: Check for return value from sb_set_blocksize") Fixes: ac27a0ec112a ("ext4: initial copy of files from ext3") Link: https://lore.kernel.org/r/20210521075533.95732-1-amakhalov@vmware.com Signed-off-by: Alexey Makhalov Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman

ext4: fix error code in ext4_commit_super

2021-05-12T06:40:00Z

commit f88f1466e2a2e5ca17dfada436d3efa1b03a3972 upstream. We should set the error code when ext4_commit_super check argument failed. Found in code review. Fixes: c4be0c1dc4cdc ("filesystem freeze: add error handling of write_super_lockfs/unlockfs"). Cc: stable@kernel.org Signed-off-by: Fengnan Chang Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20210402101631.561-1-changfengnan@vivo.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: always panic when errors=panic is specified

2021-05-12T06:40:00Z

commit ac2f7ca51b0929461ea49918f27c11b680f28995 upstream. Before commit 014c9caa29d3 ("ext4: make ext4_abort() use __ext4_error()"), the following series of commands would trigger a panic: 1. mount /dev/sda -o ro,errors=panic test 2. mount /dev/sda -o remount,abort test After commit 014c9caa29d3, remounting a file system using the test mount option "abort" will no longer trigger a panic. This commit will restore the behaviour immediately before commit 014c9caa29d3. (However, note that the Linux kernel's behavior has not been consistent; some previous kernel versions, including 5.4 and 4.19 similarly did not panic after using the mount option "abort".) This also makes a change to long-standing behaviour; namely, the following series commands will now cause a panic, when previously it did not: 1. mount /dev/sda -o ro,errors=panic test 2. echo test > /sys/fs/ext4/sda/trigger_fs_error However, this makes ext4's behaviour much more consistent, so this is a good thing. Cc: stable@kernel.org Fixes: 014c9caa29d3 ("ext4: make ext4_abort() use __ext4_error()") Signed-off-by: Ye Bin Link: https://lore.kernel.org/r/20210401081903.3421208-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: do not set SB_ACTIVE in ext4_orphan_cleanup()

2021-05-12T06:40:00Z

commit 72ffb49a7b623c92a37657eda7cc46a06d3e8398 upstream. When CONFIG_QUOTA is enabled, if we failed to mount the filesystem due to some error happens behind ext4_orphan_cleanup(), it will end up triggering a after free issue of super_block. The problem is that ext4_orphan_cleanup() will set SB_ACTIVE flag if CONFIG_QUOTA is enabled, after we cleanup the truncated inodes, the last iput() will put them into the lru list, and these inodes' pages may probably dirty and will be write back by the writeback thread, so it could be raced by freeing super_block in the error path of mount_bdev(). After check the setting of SB_ACTIVE flag in ext4_orphan_cleanup(), it was used to ensure updating the quota file properly, but evict inode and trash data immediately in the last iput does not affect the quotafile, so setting the SB_ACTIVE flag seems not required[1]. Fix this issue by just remove the SB_ACTIVE setting. [1] https://lore.kernel.org/linux-ext4/99cce8ca-e4a0-7301-840f-2ace67c551f3@huawei.com/T/#m04990cfbc4f44592421736b504afcc346b2a7c00 Cc: stable@kernel.org Signed-off-by: Zhang Yi Tested-by: Jan Kara Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20210331033138.918975-1-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: fix timer use-after-free on failed mount

2021-03-21T04:27:49Z

When filesystem mount fails because of corrupted filesystem we first cancel the s_err_report timer reminding fs errors every day and only then we flush s_error_work. However s_error_work may report another fs error and re-arm timer thus resulting in timer use-after-free. Fix the problem by first flushing the work and only after that canceling the s_err_report timer. Reported-by: syzbot+628472a2aac693ab0fcd@syzkaller.appspotmail.com Fixes: 2d01ddc86606 ("ext4: save error info to sb through journal if available") CC: stable@vger.kernel.org Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20210315165906.2175-1-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: shrink race window in ext4_should_retry_alloc()

2021-03-06T16:56:10Z

When generic/371 is run on kvm-xfstests using 5.10 and 5.11 kernels, it fails at significant rates on the two test scenarios that disable delayed allocation (ext3conv and data_journal) and force actual block allocation for the fallocate and pwrite functions in the test. The failure rate on 5.10 for both ext3conv and data_journal on one test system typically runs about 85%. On 5.11, the failure rate on ext3conv sometimes drops to as low as 1% while the rate on data_journal increases to nearly 100%. The observed failures are largely due to ext4_should_retry_alloc() cutting off block allocation retries when s_mb_free_pending (used to indicate that a transaction in progress will free blocks) is 0. However, free space is usually available when this occurs during runs of generic/371. It appears that a thread attempting to allocate blocks is just missing transaction commits in other threads that increase the free cluster count and reset s_mb_free_pending while the allocating thread isn't running. Explicitly testing for free space availability avoids this race. The current code uses a post-increment operator in the conditional expression that determines whether the retry limit has been exceeded. This means that the conditional expression uses the value of the retry counter before it's increased, resulting in an extra retry cycle. The current code actually retries twice before hitting its retry limit rather than once. Increasing the retry limit to 3 from the current actual maximum retry count of 2 in combination with the change described above reduces the observed failure rate to less that 0.1% on both ext3conv and data_journal with what should be limited impact on users sensitive to the overhead caused by retries. A per filesystem percpu counter exported via sysfs is added to allow users or developers to track the number of times the retry limit is exceeded without resorting to debugging methods. This should provide some insight into worst case retry behavior. Signed-off-by: Eric Whitney Link: https://lore.kernel.org/r/20210218151132.19678-1-enwlinux@gmail.com Signed-off-by: Theodore Ts'o