kernel/linux.git/fs/f2fs/sysfs.c, branch v7.0.10

f2fs: protect extension_list reading with sb_lock in f2fs_sbi_show()

2026-05-23T11:09:16+00:00

[ Upstream commit 5909bedbed38c558bee7cb6758ceedf9bc3a9194 ] In f2fs_sbi_show(), the extension_list, extension_count and hot_ext_count are read without holding sbi->sb_lock. If a concurrent sysfs store modifies the extension list via f2fs_update_extension_list(), the show path may read inconsistent count and array contents, potentially leading to out-of-bounds access or displaying stale data. Fix this by holding sb_lock around the entire extension list read and format operation. Fixes: b6a06cbbb5f7 ("f2fs: support hot file extension") Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin

f2fs: fix uninitialized kobject put in f2fs_init_sysfs()

2026-05-14T13:31:18+00:00

commit b635f2ecdb5ad34f9c967cabb704d6bed9382fd0 upstream. In f2fs_init_sysfs(), all failure paths after kset_register() jump to put_kobject, which unconditionally releases both f2fs_tune and f2fs_feat. If kobject_init_and_add(&f2fs_feat, ...) fails, f2fs_tune has not been initialized yet, so calling kobject_put(&f2fs_tune) is invalid. Fix this by splitting the unwind path so each error path only releases objects that were successfully initialized. Fixes: a907f3a68ee26ba4 ("f2fs: add a sysfs entry to reclaim POSIX_FADV_NOREUSE pages") Cc: stable@vger.kernel.org Signed-off-by: Guangshuo Li Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman

f2fs: sysfs: introduce critical_task_priority

2026-02-10T20:53:21+00:00

This patch introduces /sys/fs/f2fs//critical_task_priority, w/ this new sysfs interface, we can tune priority of f2fs_ckpt thread and f2fs_gc thread. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix lock priority inversion issue

2026-01-31T03:24:39+00:00

If userspace thread has held f2fs rw semaphore, due to its low priority, it could be runnable or preempted state for long time, during the time, it will block high priority thread which is trying to grab the same rw semaphore, e.g. cp_rwsem, io_rwsem... To fix such issue, let's detect thread's priority when it tries to grab f2fs_rwsem lock, if the priority is lower than a priority threshold, let's uplift the priority before it enters into critical region of lock, and restore the priority after it leaves from critical region. Meanwhile, introducing two new sysfs nodes: - /sys/fs/f2fs//adjust_lock_priority, it is used to control whether the functionality is enable or not. ========== ================== Flag_Value Flag_Description ========== ================== 0x00000000 Disabled (default) 0x00000001 cp_rwsem 0x00000002 node_change 0x00000004 node_write 0x00000008 gc_lock 0x00000010 cp_global 0x00000020 io_rwsem ========== ================== - /sys/fs/f2fs//lock_duration_priority, it is used to control priority threshold. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix to show simulate_lock_timeout correctly

2026-01-27T02:45:58+00:00

Commit d36de29f4bb5 ("f2fs: sysfs: introduce inject_lock_timeout") introduces a bug as below, fix it. cat /sys/fs/f2fs/vdx/inject_lock_timeout s/fs/f2fs/vdx/inject_lock_timeout: Invalid argument Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix to check sysfs filename w/ gc_pin_file_thresh correctly

2026-01-07T03:17:09+00:00

Sysfs entry name is gc_pin_file_thresh instead of gc_pin_file_threshold, fix it. Cc: stable@kernel.org Fixes: c521a6ab4ad7 ("f2fs: fix to limit gc_pin_file_threshold") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: fix out-of-bounds access in sysfs attribute read/write

2026-01-07T03:17:08+00:00

Some f2fs sysfs attributes suffer from out-of-bounds memory access and incorrect handling of integer values whose size is not 4 bytes. For example: vm:~# echo 65537 > /sys/fs/f2fs/vde/carve_out vm:~# cat /sys/fs/f2fs/vde/carve_out 65537 vm:~# echo 4294967297 > /sys/fs/f2fs/vde/atgc_age_threshold vm:~# cat /sys/fs/f2fs/vde/atgc_age_threshold 1 carve_out maps to {struct f2fs_sb_info}->carve_out, which is a 8-bit integer. However, the sysfs interface allows setting it to a value larger than 255, resulting in an out-of-range update. atgc_age_threshold maps to {struct atgc_management}->age_threshold, which is a 64-bit integer, but its sysfs interface cannot correctly set values larger than UINT_MAX. The root causes are: 1. __sbi_store() treats all default values as unsigned int, which prevents updating integers larger than 4 bytes and causes out-of-bounds writes for integers smaller than 4 bytes. 2. f2fs_sbi_show() also assumes all default values are unsigned int, leading to out-of-bounds reads and incorrect access to integers larger than 4 bytes. This patch introduces {struct f2fs_attr}->size to record the actual size of the integer associated with each sysfs attribute. With this information, sysfs read and write operations can correctly access and update values according to their real data size, avoiding memory corruption and truncation. Fixes: b59d0bae6ca3 ("f2fs: add sysfs support for controlling the gc_thread") Cc: stable@kernel.org Signed-off-by: Jinbao Liu Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: sysfs: introduce inject_lock_timeout

2026-01-07T03:17:08+00:00

This patch adds a new sysfs node in /sys/fs/f2fs//inject_lock_timeout, it relies on CONFIG_F2FS_FAULT_INJECTION kernel config. It can be used to simulate different type of timeout in lock duration. ========== =============================== Flag_Value Flag_Description ========== =============================== 0x00000000 No timeout (default) 0x00000001 Simulate running time 0x00000002 Simulate IO type sleep time 0x00000003 Simulate Non-IO type sleep time 0x00000004 Simulate runnable time ========== =============================== Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: sysfs: introduce max_lock_elapsed_time

2026-01-07T03:17:06+00:00

This patch add a new sysfs node in /sys/fs/f2fs//max_lock_elapsed_time. This is a threshold, once a thread enters critical region that lock covers, total elapsed time exceeds this threshold, f2fs will print tracepoint to dump information of related context. This sysfs entry can be used to control the value of threshold, by default, the value is 500 ms. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim

f2fs: add a sysfs entry to show max open zones

2025-12-04T02:00:04+00:00

This patch adds a sysfs entry showing the max zones that F2FS can write concurrently. Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim