KASAN: use-after-free Read in ext4_find_extent (4)

[ALBIN BABU VARGHESE]

#syz test

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
kernel panic: KASAN: panic_on_warn set ...

>ffff88806ecb8c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88806ecb8c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806ecb8d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
Kernel panic - not syncing: KASAN: panic_on_warn set ...
CPU: 1 UID: 0 PID: 15465 Comm: syz.0.2193 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>
dump_stack_lvl+0x99/0x250 lib/dump_stack.c:120
vpanic+0x237/0x6d0 kernel/panic.c:489
panic+0xb9/0xc0 kernel/panic.c:626
check_panic_on_warn+0x89/0xb0 kernel/panic.c:376
end_report+0x78/0x160 mm/kasan/report.c:227
kasan_report+0x129/0x150 mm/kasan/report.c:597
ext4_ext_rm_leaf fs/ext4/extents.c:2630 [inline]
ext4_ext_remove_space+0x3211/0x42f0 fs/ext4/extents.c:2968
ext4_ext_truncate+0x17e/0x300 fs/ext4/extents.c:4487
ext4_truncate+0xb4f/0x12e0 fs/ext4/inode.c:4614
ext4_truncate_failed_write fs/ext4/truncate.h:22 [inline]
ext4_write_end+0x76e/0x9f0 fs/ext4/inode.c:1486
ext4_da_write_end+0x84/0xcf0 fs/ext4/inode.c:3277
generic_perform_write+0x62a/0x900 mm/filemap.c:4275
ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:299
ext4_file_write_iter+0x298/0x1bc0 fs/ext4/file.c:-1
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_pwrite64 fs/read_write.c:793 [inline]
__do_sys_pwrite64 fs/read_write.c:801 [inline]
__se_sys_pwrite64 fs/read_write.c:798 [inline]
__x64_sys_pwrite64+0x193/0x220 fs/read_write.c:798
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd18e38e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd18f1a9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007fd18e5b5fa0 RCX: 00007fd18e38e929
RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007fd18e410b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000e7c R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd18e5b5fa0 R15: 00007ffe86830148
</TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..


Tested on:

commit: 8b690556 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1419e97c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=1144b212580000

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

KASAN: use-after-free Read in ext4_find_extent

loop0: detected capacity change from 0 to 1024
EXT4-fs: Ignoring removed oldalloc option
EXT4-fs: Ignoring removed orlov option
EXT4-fs (loop0): stripe (1570) is not aligned with cluster size (16), stripe is disabled
==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:841 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xae6/0xcc0 fs/ext4/extents.c:956
Read of size 4 at addr ffff88805848d018 by task syz.0.1716/13445

CPU: 1 UID: 0 PID: 13445 Comm: syz.0.1716 Not tainted syzkaller #0 PREEMPT(full)

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
<TASK>

dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
ext4_ext_binsearch fs/ext4/extents.c:841 [inline]
ext4_find_extent+0xae6/0xcc0 fs/ext4/extents.c:956
ext4_ext_map_blocks+0x288/0x6ac0 fs/ext4/extents.c:4208
ext4_map_query_blocks+0x13b/0x930 fs/ext4/inode.c:550
ext4_map_blocks+0x4b3/0x1740 fs/ext4/inode.c:773
_ext4_get_block+0x200/0x4c0 fs/ext4/inode.c:910
ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:943
ext4_block_write_begin+0x993/0x1710 fs/ext4/inode.c:1198
ext4_write_begin+0xc04/0x19a0 fs/ext4/ext4_jbd2.h:-1
ext4_da_write_begin+0x445/0xda0 fs/ext4/inode.c:3129
generic_perform_write+0x2c5/0x900 mm/filemap.c:4254

ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:299
ext4_file_write_iter+0x298/0x1bc0 fs/ext4/file.c:-1
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_pwrite64 fs/read_write.c:793 [inline]
__do_sys_pwrite64 fs/read_write.c:801 [inline]
__se_sys_pwrite64 fs/read_write.c:798 [inline]
__x64_sys_pwrite64+0x193/0x220 fs/read_write.c:798
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7fb6d7d8e929

Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007fb6d8cd4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007fb6d7fb5fa0 RCX: 00007fb6d7d8e929

RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000004

RBP: 00007fb6d7e10b39 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000e7c R11: 0000000000000246 R12: 0000000000000000

R13: 0000000000000000 R14: 00007fb6d7fb5fa0 R15: 00007ffe519db498
</TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xc00772c pfn:0x5848d
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 000000000c00772c 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|__GFP_COMP), pid 6135, tgid 6130 (syz-execprog), ts 118165039414, free_ts 376890617757
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0x2356/0x2430 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
folio_alloc_mpol_noprof mm/mempolicy.c:2435 [inline]
vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2470
folio_prealloc+0x30/0x180 mm/memory.c:-1
alloc_anon_folio mm/memory.c:5126 [inline]
do_anonymous_page mm/memory.c:5183 [inline]
do_pte_missing mm/memory.c:4360 [inline]
handle_pte_fault mm/memory.c:6195 [inline]
__handle_mm_fault+0x2a8b/0x5400 mm/memory.c:6336
handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6505
do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
page last free pid 6132 tgid 6130 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
free_unref_folios+0xe5d/0x15f0 mm/page_alloc.c:2958
folios_put_refs+0x584/0x670 mm/swap.c:1002
free_pages_and_swap_cache+0x277/0x520 mm/swap_state.c:355
__tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:397 [inline]
tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
madvise_finish_tlb mm/madvise.c:1790 [inline]
do_madvise+0x208/0x270 mm/madvise.c:1979
__do_sys_madvise mm/madvise.c:1987 [inline]
__se_sys_madvise mm/madvise.c:1985 [inline]
__x64_sys_madvise+0xa7/0xc0 mm/madvise.c:1985

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff88805848cf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88805848cf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805848d000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88805848d080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88805848d100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Tested on:

commit: 8b690556 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream

console output: https://syzkaller.appspot.com/x/log.txt?x=12e90742580000

kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=169cce0a580000

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in ext4_find_extent

==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:841 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xae6/0xcc0 fs/ext4/extents.c:956

Read of size 4 at addr ffff888060ccb018 by task kworker/u8:0/12

CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025

Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work

Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
ext4_ext_binsearch fs/ext4/extents.c:841 [inline]
ext4_find_extent+0xae6/0xcc0 fs/ext4/extents.c:956
ext4_ext_map_blocks+0x288/0x6ac0 fs/ext4/extents.c:4208

ext4_map_create_blocks fs/ext4/inode.c:609 [inline]
ext4_map_blocks+0x860/0x1740 fs/ext4/inode.c:811
ext4_convert_unwritten_extents+0x2ae/0x5d0 fs/ext4/extents.c:4976
ext4_convert_unwritten_io_end_vec+0xff/0x170 fs/ext4/extents.c:5016
ext4_end_io_end+0xc7/0x410 fs/ext4/page-io.c:199
ext4_do_flush_completed_IO fs/ext4/page-io.c:290 [inline]
ext4_end_io_rsv_work+0x262/0x330 fs/ext4/page-io.c:305
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

</TASK>

The buggy address belongs to the physical page:

page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x60ccb

flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000

raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000

page dumped because: kasan: bad access detected
page_owner tracks the page as freed

page last allocated via order 0, migratetype Movable, gfp_mask 0x148c48(GFP_NOFS|__GFP_MOVABLE|__GFP_NOFAIL|__GFP_COMP|__GFP_HARDWALL), pid 10925, tgid 10924 (syz.0.1091), ts 292203567761, free_ts 292265476069

set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0x2356/0x2430 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416

alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
alloc_pages_noprof+0xa9/0x190 mm/mempolicy.c:2507
folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2517
filemap_alloc_folio_noprof+0xdf/0x470 mm/filemap.c:1020
__filemap_get_folio+0x3f2/0xaf0 mm/filemap.c:2012
grow_dev_folio fs/buffer.c:1050 [inline]
grow_buffers fs/buffer.c:1116 [inline]
__getblk_slow fs/buffer.c:1134 [inline]
bdev_getblk+0x1ad/0x660 fs/buffer.c:1461
__getblk include/linux/buffer_head.h:380 [inline]
sb_getblk include/linux/buffer_head.h:386 [inline]
__ext4_get_inode_loc+0x561/0x1040 fs/ext4/inode.c:4837
__ext4_get_inode_loc_noinmem fs/ext4/inode.c:4950 [inline]
__ext4_iget+0x451/0x4220 fs/ext4/inode.c:5225
__ext4_fill_super fs/ext4/super.c:5512 [inline]
ext4_fill_super+0x4637/0x61e0 fs/ext4/super.c:5736
get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1698
vfs_get_tree+0x92/0x2b0 fs/super.c:1758
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3642 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3718
do_mount fs/namespace.c:4041 [inline]
__do_sys_mount fs/namespace.c:4229 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4206
page last free pid 8941 tgid 8941 stack trace:

reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
free_unref_folios+0xe5d/0x15f0 mm/page_alloc.c:2958
folios_put_refs+0x584/0x670 mm/swap.c:1002

folio_batch_release include/linux/pagevec.h:101 [inline]
mapping_try_invalidate+0x324/0x410 mm/truncate.c:579
ext4_put_super+0x813/0xc40 fs/ext4/super.c:1348
generic_shutdown_super+0x135/0x2c0 fs/super.c:642
kill_block_super+0x44/0x90 fs/super.c:1729
ext4_kill_sb+0x68/0xb0 fs/ext4/super.c:7403
deactivate_locked_super+0xbc/0x130 fs/super.c:473
cleanup_mnt+0x425/0x4c0 fs/namespace.c:1318
task_work_run+0x1d4/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100

entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:

ffff888060ccaf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888060ccaf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888060ccb000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff888060ccb080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888060ccb100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


Tested on:

commit: 23cb64fb Merge tag 'soc-fixes-6.18-3' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=128cba12580000

kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=14657692580000

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in ext4_find_extent

==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:841 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xae6/0xcc0 fs/ext4/extents.c:956

Read of size 4 at addr ffff88806fbac08c by task kworker/u8:3/49

CPU: 0 UID: 0 PID: 49 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full)

page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7fdb995cf pfn:0x6fbac
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001899f48 ffffea0001a80508 0000000000000000
raw: 00000007fdb995cf 0000000000000000 00000000ffffffff 0000000000000000

page dumped because: kasan: bad access detected
page_owner tracks the page as freed

page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|__GFP_COMP), pid 6178, tgid 6178 (udevd), ts 265882608890, free_ts 265892368035

set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0x2356/0x2430 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416

folio_alloc_mpol_noprof mm/mempolicy.c:2435 [inline]
vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2470
folio_prealloc+0x30/0x180 mm/memory.c:-1
alloc_anon_folio mm/memory.c:5126 [inline]
do_anonymous_page mm/memory.c:5183 [inline]
do_pte_missing mm/memory.c:4360 [inline]
handle_pte_fault mm/memory.c:6195 [inline]
__handle_mm_fault+0x2a8b/0x5400 mm/memory.c:6336
handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6505

do_user_addr_fault+0x764/0x1380 arch/x86/mm/fault.c:1387

handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

page last free pid 6178 tgid 6178 stack trace:

reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
free_unref_folios+0xe5d/0x15f0 mm/page_alloc.c:2958
folios_put_refs+0x584/0x670 mm/swap.c:1002

folios_put include/linux/mm.h:1484 [inline]
folio_batch_move_lru+0x2a5/0x330 mm/swap.c:179
lru_add_drain_cpu+0x119/0x880 mm/swap.c:648
lru_add_drain+0x122/0x3e0 mm/swap.c:737
__folio_batch_release+0x48/0x90 mm/swap.c:1059
folio_batch_release include/linux/pagevec.h:101 [inline]
shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1119
shmem_truncate_range mm/shmem.c:1231 [inline]
shmem_evict_inode+0x272/0xa70 mm/shmem.c:1359
evict+0x504/0x9c0 fs/inode.c:810
__dentry_kill+0x209/0x660 fs/dcache.c:669
dput+0x19f/0x2b0 fs/dcache.c:911
do_renameat2+0x6b2/0xa50 fs/namei.c:5366
__do_sys_rename fs/namei.c:5411 [inline]
__se_sys_rename fs/namei.c:5409 [inline]
__x64_sys_rename+0x82/0x90 fs/namei.c:5409

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94

entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:

ffff88806fbabf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88806fbac000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806fbac080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88806fbac100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806fbac180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

==================================================================


Tested on:

commit: 23cb64fb Merge tag 'soc-fixes-6.18-3' of git://git.ker..
git tree: upstream

console output: https://syzkaller.appspot.com/x/log.txt?x=166c0514580000

kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=12f57692580000

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in ext4_find_extent

==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:841 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xae6/0xcc0 fs/ext4/extents.c:956

Read of size 4 at addr ffff88805f4ebd18 by task kworker/u8:3/50

CPU: 1 UID: 0 PID: 50 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full)

page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x4 pfn:0x5f4eb
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001ab2448 ffffea0001b7a848 0000000000000000
raw: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000

page dumped because: kasan: bad access detected
page_owner tracks the page as freed

page last allocated via order 0, migratetype Movable, gfp_mask 0x141cca(GFP_HIGHUSER_MOVABLE|__GFP_WRITE|__GFP_COMP), pid 6484, tgid 6483 (syz.0.20), ts 137862241539, free_ts 137891188282

set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0x2356/0x2430 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416

alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
alloc_pages_noprof+0xa9/0x190 mm/mempolicy.c:2507
folio_alloc_noprof+0x1e/0x30 mm/mempolicy.c:2517
filemap_alloc_folio_noprof+0xdf/0x470 mm/filemap.c:1020
__filemap_get_folio+0x3f2/0xaf0 mm/filemap.c:2012

write_begin_get_folio include/linux/pagemap.h:784 [inline]
ext4_write_begin+0x4c8/0x19a0 fs/ext4/inode.c:1318

ext4_da_write_begin+0x445/0xda0 fs/ext4/inode.c:3129
generic_perform_write+0x2c5/0x900 mm/filemap.c:4254
ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:299
ext4_file_write_iter+0x298/0x1bc0 fs/ext4/file.c:-1
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_pwrite64 fs/read_write.c:793 [inline]
__do_sys_pwrite64 fs/read_write.c:801 [inline]
__se_sys_pwrite64 fs/read_write.c:798 [inline]
__x64_sys_pwrite64+0x193/0x220 fs/read_write.c:798

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94

page last free pid 6341 tgid 6341 stack trace:

reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
free_unref_folios+0xe5d/0x15f0 mm/page_alloc.c:2958
folios_put_refs+0x584/0x670 mm/swap.c:1002

folio_batch_release include/linux/pagevec.h:101 [inline]
truncate_inode_pages_range+0x346/0xda0 mm/truncate.c:408
ext4_evict_inode+0x1aa/0xee0 fs/ext4/inode.c:185
evict+0x504/0x9c0 fs/inode.c:810
dispose_list fs/inode.c:852 [inline]
evict_inodes+0x64c/0x6d0 fs/inode.c:906
generic_shutdown_super+0x9a/0x2c0 fs/super.c:627

kill_block_super+0x44/0x90 fs/super.c:1729
ext4_kill_sb+0x68/0xb0 fs/ext4/super.c:7403
deactivate_locked_super+0xbc/0x130 fs/super.c:473
cleanup_mnt+0x425/0x4c0 fs/namespace.c:1318
task_work_run+0x1d4/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100

entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:

ffff88805f4ebc00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88805f4ebc80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88805f4ebd00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88805f4ebd80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88805f4ebe00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

==================================================================


Tested on:

commit: 23cb64fb Merge tag 'soc-fixes-6.18-3' of git://git.ker..
git tree: upstream

console output: https://syzkaller.appspot.com/x/log.txt?x=12608c2a580000

kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=16dbca12580000

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in ext4_find_extent

==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:841 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xae6/0xcc0 fs/ext4/extents.c:956

Read of size 4 at addr ffff8880618f1018 by task kworker/u8:6/1096

CPU: 1 UID: 0 PID: 1096 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full)

page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7f8288ec9 pfn:0x618f1
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001863c88 ffffea0001863c08 0000000000000000
raw: 00000007f8288ec9 0000000000000000 00000000ffffffff 0000000000000000

page dumped because: kasan: bad access detected
page_owner tracks the page as freed

page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|__GFP_COMP), pid 6155, tgid 6155 (syz-executor), ts 131175623082, free_ts 136501716604

set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0x2356/0x2430 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416

folio_alloc_mpol_noprof mm/mempolicy.c:2435 [inline]
vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2470
folio_prealloc+0x30/0x180 mm/memory.c:-1
alloc_anon_folio mm/memory.c:5126 [inline]
do_anonymous_page mm/memory.c:5183 [inline]
do_pte_missing mm/memory.c:4360 [inline]
handle_pte_fault mm/memory.c:6195 [inline]
__handle_mm_fault+0x2a8b/0x5400 mm/memory.c:6336
handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6505

do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336

handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

page last free pid 6155 tgid 6155 stack trace:

reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
free_unref_folios+0xe5d/0x15f0 mm/page_alloc.c:2958
folios_put_refs+0x584/0x670 mm/swap.c:1002

free_pages_and_swap_cache+0x277/0x520 mm/swap_state.c:355
__tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:397 [inline]
tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497

vms_clear_ptes+0x42c/0x540 mm/vma.c:1235
vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1277
do_vmi_align_munmap+0x364/0x440 mm/vma.c:1536
do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584
__vm_munmap+0x207/0x380 mm/vma.c:3156
__do_sys_munmap mm/mmap.c:1080 [inline]
__se_sys_munmap mm/mmap.c:1077 [inline]
__x64_sys_munmap+0x60/0x70 mm/mmap.c:1077

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94

entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:

ffff8880618f0f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8880618f0f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880618f1000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff8880618f1080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8880618f1100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

==================================================================


Tested on:

commit: 23cb64fb Merge tag 'soc-fixes-6.18-3' of git://git.ker..
git tree: upstream

console output: https://syzkaller.appspot.com/x/log.txt?x=1002f692580000

kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=111dba12580000

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+ee60e5...@syzkaller.appspotmail.com
Tested-by: syzbot+ee60e5...@syzkaller.appspotmail.com

Tested on:

commit: 23cb64fb Merge tag 'soc-fixes-6.18-3' of git://git.ker..
git tree: upstream

console output: https://syzkaller.appspot.com/x/log.txt?x=159b997c580000

kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=13abba12580000

Note: testing is done by a robot and is best-effort only.

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in ext4_find_extent

==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:841 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xae6/0xcc0 fs/ext4/extents.c:956

Read of size 4 at addr ffff888072543018 by task kworker/u8:3/49

CPU: 1 UID: 0 PID: 49 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full)

page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7f7902757 pfn:0x72543
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 00000007f7902757 0000000000000000 00000000ffffffff 0000000000000000

page dumped because: kasan: bad access detected
page_owner tracks the page as freed

page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|__GFP_COMP), pid 6138, tgid 6138 (syz-executor), ts 130428789605, free_ts 136080635031

set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0x2356/0x2430 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
folio_alloc_mpol_noprof mm/mempolicy.c:2435 [inline]
vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2470
folio_prealloc+0x30/0x180 mm/memory.c:-1
alloc_anon_folio mm/memory.c:5126 [inline]
do_anonymous_page mm/memory.c:5183 [inline]
do_pte_missing mm/memory.c:4360 [inline]
handle_pte_fault mm/memory.c:6195 [inline]
__handle_mm_fault+0x2a8b/0x5400 mm/memory.c:6336
handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6505
do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

page last free pid 6138 tgid 6138 stack trace:

reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
free_unref_folios+0xe5d/0x15f0 mm/page_alloc.c:2958
folios_put_refs+0x584/0x670 mm/swap.c:1002
free_pages_and_swap_cache+0x277/0x520 mm/swap_state.c:355
__tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:397 [inline]
tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
vms_clear_ptes+0x42c/0x540 mm/vma.c:1235
vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1277
do_vmi_align_munmap+0x364/0x440 mm/vma.c:1536
do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584
__vm_munmap+0x207/0x380 mm/vma.c:3156
__do_sys_munmap mm/mmap.c:1080 [inline]
__se_sys_munmap mm/mmap.c:1077 [inline]
__x64_sys_munmap+0x60/0x70 mm/mmap.c:1077
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:

ffff888072542f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888072542f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888072543000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff888072543080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888072543100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


Tested on:

commit: 8e621c9a Merge tag 'net-6.18-rc7' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10bc2a12580000

kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=11f6f692580000

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in ext4_find_extent

==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch fs/ext4/extents.c:841 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0xae6/0xcc0 fs/ext4/extents.c:956

Read of size 4 at addr ffff88806ecb8e18 by task kworker/u8:9/3520

CPU: 1 UID: 0 PID: 3520 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full)

page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x2f pfn:0x6ecb8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001bb2dc8 ffffea0001bb2e48 0000000000000000
raw: 000000000000002f 0000000000000000 00000000ffffffff 0000000000000000

page dumped because: kasan: bad access detected
page_owner tracks the page as freed

page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 8356, tgid 8355 (syz.0.469), ts 208003260519, free_ts 208144424942

set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845
prep_new_page mm/page_alloc.c:1853 [inline]
get_page_from_freelist+0x2356/0x2430 mm/page_alloc.c:3879
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416

folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2435
shmem_alloc_folio mm/shmem.c:1870 [inline]
shmem_alloc_and_add_folio+0x423/0xf40 mm/shmem.c:1912
shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2535
shmem_get_folio mm/shmem.c:2641 [inline]
shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3291
generic_perform_write+0x2c5/0x900 mm/filemap.c:4254
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3466

new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686

ksys_write+0x145/0x250 fs/read_write.c:738

do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

page last free pid 6436 tgid 6436 stack trace:

reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
free_unref_folios+0xe5d/0x15f0 mm/page_alloc.c:2958
folios_put_refs+0x584/0x670 mm/swap.c:1002

folio_batch_release include/linux/pagevec.h:101 [inline]
shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1119
shmem_truncate_range mm/shmem.c:1231 [inline]
shmem_evict_inode+0x272/0xa70 mm/shmem.c:1359
evict+0x504/0x9c0 fs/inode.c:810
__dentry_kill+0x209/0x660 fs/dcache.c:669
dput+0x19f/0x2b0 fs/dcache.c:911

__fput+0x68e/0xa70 fs/file_table.c:476

task_work_run+0x1d4/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100

entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:

ffff88806ecb8d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806ecb8d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806ecb8e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88806ecb8e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806ecb8f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

==================================================================


Tested on:

commit: 8e621c9a Merge tag 'net-6.18-rc7' of git://git.kernel...
git tree: upstream

console output: https://syzkaller.appspot.com/x/log.txt?x=14babe0a580000

kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=115ef692580000

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+ee60e5...@syzkaller.appspotmail.com
Tested-by: syzbot+ee60e5...@syzkaller.appspotmail.com

Tested on:

commit: 2eba5e05 Merge tag 'loongarch-fixes-6.18-2' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10454c2a580000

kernel config: https://syzkaller.appspot.com/x/.config?x=6e611fe59206f39f
dashboard link: https://syzkaller.appspot.com/bug?extid=ee60e584b5c6bb229126
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=13a1aa12580000