CVE-2026-46194 is a vulnerability in Linux Kernel
Published on May 28, 2026
f2fs: fix node_cnt race between extent node destroy and writeback
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix node_cnt race between extent node destroy and writeback
f2fs_destroy_extent_node() does not set FI_NO_EXTENT before clearing
extent nodes. When called from f2fs_drop_inode() with I_SYNC set,
concurrent kworker writeback can insert new extent nodes into the same
extent tree, racing with the destroy and triggering f2fs_bug_on() in
__destroy_extent_node(). The scenario is as follows:
drop inode writeback
- iput
- f2fs_drop_inode // I_SYNC set
- f2fs_destroy_extent_node
- __destroy_extent_node
- while (node_cnt) {
write_lock(&et->lock)
__free_extent_tree
write_unlock(&et->lock)
- __writeback_single_inode
- f2fs_outplace_write_data
- f2fs_update_read_extent_cache
- __update_extent_tree_range
// FI_NO_EXTENT not set,
// insert new extent node
} // node_cnt == 0, exit while
- f2fs_bug_on(node_cnt) // node_cnt > 0
Additionally, __update_extent_tree_range() only checks FI_NO_EXTENT for
EX_READ type, leaving EX_BLOCK_AGE updates completely unprotected.
This patch set FI_NO_EXTENT under et->lock in __destroy_extent_node(),
consistent with other callers (__update_extent_tree_range and
__drop_extent_tree) and check FI_NO_EXTENT for both EX_READ and
EX_BLOCK_AGE tree.
Products Associated with CVE-2026-46194
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Affected Versions
Linux:- Version 295b50e95e900da31ff237e46e04525fa799b2cf and below 42dd1c91f993431d0b399502479d00e6ad1bca71 is affected.
- Version 924f7dd1e832e4e4530d14711db223d2803f7b61 and below ab1eaf9d5c99042f5b0243bf67a06283a4c0757f is affected.
- Version 3fc5d5a182f6a1f8bd4dc775feb54c369dd2c343 and below b0e4395870eb3441ddc959f6710b5f6ca61aff26 is affected.
- Version 3fc5d5a182f6a1f8bd4dc775feb54c369dd2c343 and below 0559a0e962aacbb47519e26ee663be04b72dcb92 is affected.
- Version 3fc5d5a182f6a1f8bd4dc775feb54c369dd2c343 and below ed78aeebef05212ef7dca93bd931e4eff67c113f is affected.
- Version 6.6.66 and below 6.6.140 is affected.
- Version 6.12.5 and below 6.12.88 is affected.
- Version 6.13 is affected.
- Before 6.13 is unaffected.
- Version 6.6.140, <= 6.6.* is unaffected.
- Version 6.12.88, <= 6.12.* is unaffected.
- Version 6.18.30, <= 6.18.* is unaffected.
- Version 7.0.7, <= 7.0.* is unaffected.
- Version 7.1-rc1, <= * is unaffected.