syzbot

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BUG: KMSAN: uninit-value in __is_extent_mergeable fs/f2fs/extent_cache.c:154 [inline]
BUG: KMSAN: uninit-value in __is_back_mergeable fs/f2fs/extent_cache.c:173 [inline]
BUG: KMSAN: uninit-value in __try_merge_extent_node+0x415/0x1600 fs/f2fs/extent_cache.c:546
 __is_extent_mergeable fs/f2fs/extent_cache.c:154 [inline]
 __is_back_mergeable fs/f2fs/extent_cache.c:173 [inline]
 __try_merge_extent_node+0x415/0x1600 fs/f2fs/extent_cache.c:546
 __update_extent_tree_range+0x1b53/0x2ae0 fs/f2fs/extent_cache.c:776
 __update_extent_cache+0x11cc/0x1420 fs/f2fs/extent_cache.c:950
 f2fs_update_read_extent_cache+0x20/0x30 fs/f2fs/extent_cache.c:1055
 f2fs_update_data_blkaddr+0x428/0x470 fs/f2fs/data.c:1142
 f2fs_outplace_write_data+0x1bf/0x250 fs/f2fs/segment.c:4011
 f2fs_do_write_data_page+0x2a11/0x3480 fs/f2fs/data.c:2752
 f2fs_write_single_data_page+0x15bf/0x29b0 fs/f2fs/data.c:2868
 f2fs_write_cache_pages fs/f2fs/data.c:3133 [inline]
 __f2fs_write_data_pages fs/f2fs/data.c:3282 [inline]
 f2fs_write_data_pages+0x2f66/0x5480 fs/f2fs/data.c:3309
 do_writepages+0x3ef/0x860 mm/page-writeback.c:2636
 filemap_fdatawrite_wbc mm/filemap.c:386 [inline]
 __filemap_fdatawrite_range mm/filemap.c:419 [inline]
 file_write_and_wait_range+0x6f0/0x7d0 mm/filemap.c:794
 f2fs_do_sync_file+0x79b/0x31c0 fs/f2fs/file.c:294
 f2fs_sync_file+0x107/0x180 fs/f2fs/file.c:411
 vfs_fsync_range+0x19e/0x240 fs/sync.c:187
 generic_write_sync include/linux/fs.h:3031 [inline]
 f2fs_file_write_iter+0xddf/0x4990 fs/f2fs/file.c:5241
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xb48/0x1580 fs/read_write.c:686
 ksys_write fs/read_write.c:738 [inline]
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746
 x64_sys_call+0x38c3/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 __attach_extent_node+0x27c/0x630 fs/f2fs/extent_cache.c:302
 f2fs_init_read_extent_tree+0x48b/0xf10 fs/f2fs/extent_cache.c:443
 do_read_inode fs/f2fs/inode.c:541 [inline]
 f2fs_iget+0x7a0e/0x8950 fs/f2fs/inode.c:589
 f2fs_lookup+0x5c3/0x13c0 fs/f2fs/namei.c:499
 lookup_open fs/namei.c:3695 [inline]
 open_last_lookups fs/namei.c:3816 [inline]
 path_openat+0x298a/0x6760 fs/namei.c:4052
 do_filp_open+0x280/0x660 fs/namei.c:4082
 do_sys_openat2+0x1bb/0x2f0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x240/0x300 fs/open.c:1463
 x64_sys_call+0x213/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable ei created at:
 f2fs_init_read_extent_tree+0xe7/0xf10 fs/f2fs/extent_cache.c:417
 do_read_inode fs/f2fs/inode.c:541 [inline]
 f2fs_iget+0x7a0e/0x8950 fs/f2fs/inode.c:589

CPU: 1 UID: 0 PID: 21300 Comm: syz.8.4160 Tainted: G        W           6.16.0-rc7-syzkaller-00114-g327579671a9b #0 PREEMPT(none) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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