Re: [syzbot] [ext4?] KASAN: use-after-free Read in xattr_find_entry (2)
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syzbot
Mar 26, 2026, 12:59:02 PM (4 days ago) Mar 26
to karti...@gmail.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in xattr_find_entry
loop0: detected capacity change from 1024 to 64
==================================================================
BUG: KASAN: use-after-free in xattr_find_entry+0x1a5/0x280 fs/ext4/xattr.c:334
Read of size 4 at addr ffff88806233f004 by task syz.0.17/6393
CPU: 1 UID: 49663 PID: 6393 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xba/0x230 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
xattr_find_entry+0x1a5/0x280 fs/ext4/xattr.c:334
ext4_xattr_ibody_get+0x232/0x4c0 fs/ext4/xattr.c:655
ext4_xattr_get+0x123/0x6a0 fs/ext4/xattr.c:709
ext4_get_acl+0x84/0x930 fs/ext4/acl.c:165
__get_acl+0x27e/0x410 fs/posix_acl.c:159
check_acl+0x3a/0x150 fs/namei.c:385
acl_permission_check fs/namei.c:471 [inline]
generic_permission+0x497/0x690 fs/namei.c:524
do_inode_permission fs/namei.c:585 [inline]
inode_permission+0x243/0x5f0 fs/namei.c:648
lookup_inode_permission_may_exec fs/namei.c:-1 [inline]
may_lookup fs/namei.c:1973 [inline]
link_path_walk+0x1149/0x18d0 fs/namei.c:2595
path_lookupat+0xe4/0x8c0 fs/namei.c:2803
filename_lookup+0x256/0x5d0 fs/namei.c:2833
user_path_at+0x40/0x160 fs/namei.c:3612
do_mount fs/namespace.c:4169 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x2dc/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f14f759c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f14f845c028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f14f7815fa0 RCX: 00007f14f759c629
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000000
RBP: 00007f14f7632b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002094080 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f14f7816038 R14: 00007f14f7815fa0 R15: 00007ffd4455cb58
</TASK>
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x3c9 pfn:0x6233f
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea000188d008 ffffea0001cecd88 0000000000000000
raw: 00000000000003c9 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 6183, tgid 6183 (syz-executor), ts 130974047320, free_ts 131341169720
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2484
folio_alloc_mpol_noprof mm/mempolicy.c:2503 [inline]
vma_alloc_folio_noprof+0xea/0x210 mm/mempolicy.c:2538
folio_prealloc mm/memory.c:-1 [inline]
do_cow_fault mm/memory.c:5823 [inline]
do_fault mm/memory.c:5935 [inline]
do_pte_missing+0x4ea/0x3490 mm/memory.c:4477
handle_pte_fault mm/memory.c:6317 [inline]
__handle_mm_fault mm/memory.c:6455 [inline]
handle_mm_fault+0x1bec/0x3310 mm/memory.c:6624
do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
page last free pid 6184 tgid 6184 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
free_unref_folios+0xed5/0x16d0 mm/page_alloc.c:3040
folios_put_refs+0x789/0x8d0 mm/swap.c:1002
free_pages_and_swap_cache+0x2e7/0x5b0 mm/swap_state.c:423
__tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:398 [inline]
tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:405
tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:530
exit_mmap+0x498/0xa10 mm/mmap.c:1315
__mmput+0x118/0x430 kernel/fork.c:1175
exit_mm+0x168/0x220 kernel/exit.c:581
do_exit+0x6a2/0x23c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1118
get_signal+0x1284/0x1330 kernel/signal.c:3034
arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88806233ef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88806233ef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88806233f000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88806233f080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806233f100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
Tested on:
commit: 0138af24 Merge tag 'erofs-for-7.0-rc6-fixes' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13bad06a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b643133b3e44c9fd
dashboard link: https://syzkaller.appspot.com/bug?extid=fb32afec111a7d61b939
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=16da8eda580000
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in xattr_find_entry
loop0: detected capacity change from 1024 to 64
==================================================================
BUG: KASAN: use-after-free in xattr_find_entry+0x1a5/0x280 fs/ext4/xattr.c:334
Read of size 4 at addr ffff88806233f004 by task syz.0.17/6393
CPU: 1 UID: 49663 PID: 6393 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xba/0x230 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
xattr_find_entry+0x1a5/0x280 fs/ext4/xattr.c:334
ext4_xattr_ibody_get+0x232/0x4c0 fs/ext4/xattr.c:655
ext4_xattr_get+0x123/0x6a0 fs/ext4/xattr.c:709
ext4_get_acl+0x84/0x930 fs/ext4/acl.c:165
__get_acl+0x27e/0x410 fs/posix_acl.c:159
check_acl+0x3a/0x150 fs/namei.c:385
acl_permission_check fs/namei.c:471 [inline]
generic_permission+0x497/0x690 fs/namei.c:524
do_inode_permission fs/namei.c:585 [inline]
inode_permission+0x243/0x5f0 fs/namei.c:648
lookup_inode_permission_may_exec fs/namei.c:-1 [inline]
may_lookup fs/namei.c:1973 [inline]
link_path_walk+0x1149/0x18d0 fs/namei.c:2595
path_lookupat+0xe4/0x8c0 fs/namei.c:2803
filename_lookup+0x256/0x5d0 fs/namei.c:2833
user_path_at+0x40/0x160 fs/namei.c:3612
do_mount fs/namespace.c:4169 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x2dc/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f14f759c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f14f845c028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f14f7815fa0 RCX: 00007f14f759c629
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000000
RBP: 00007f14f7632b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002094080 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f14f7816038 R14: 00007f14f7815fa0 R15: 00007ffd4455cb58
</TASK>
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x3c9 pfn:0x6233f
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea000188d008 ffffea0001cecd88 0000000000000000
raw: 00000000000003c9 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 6183, tgid 6183 (syz-executor), ts 130974047320, free_ts 131341169720
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2484
folio_alloc_mpol_noprof mm/mempolicy.c:2503 [inline]
vma_alloc_folio_noprof+0xea/0x210 mm/mempolicy.c:2538
folio_prealloc mm/memory.c:-1 [inline]
do_cow_fault mm/memory.c:5823 [inline]
do_fault mm/memory.c:5935 [inline]
do_pte_missing+0x4ea/0x3490 mm/memory.c:4477
handle_pte_fault mm/memory.c:6317 [inline]
__handle_mm_fault mm/memory.c:6455 [inline]
handle_mm_fault+0x1bec/0x3310 mm/memory.c:6624
do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
page last free pid 6184 tgid 6184 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
free_unref_folios+0xed5/0x16d0 mm/page_alloc.c:3040
folios_put_refs+0x789/0x8d0 mm/swap.c:1002
free_pages_and_swap_cache+0x2e7/0x5b0 mm/swap_state.c:423
__tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:398 [inline]
tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:405
tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:530
exit_mmap+0x498/0xa10 mm/mmap.c:1315
__mmput+0x118/0x430 kernel/fork.c:1175
exit_mm+0x168/0x220 kernel/exit.c:581
do_exit+0x6a2/0x23c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1118
get_signal+0x1284/0x1330 kernel/signal.c:3034
arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88806233ef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88806233ef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88806233f000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88806233f080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806233f100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
Tested on:
commit: 0138af24 Merge tag 'erofs-for-7.0-rc6-fixes' of git://..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13bad06a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b643133b3e44c9fd
dashboard link: https://syzkaller.appspot.com/bug?extid=fb32afec111a7d61b939
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=16da8eda580000
syzbot
Mar 27, 2026, 10:05:05 AM (3 days ago) Mar 27
to karti...@gmail.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in xattr_find_entry
DEBUG: inode 12: ibody_get IFIRST=ffff88806edbcfa4 end=ffff88806edbd000 gap=92
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Read in xattr_find_entry
EXT4-fs error (device loop0): ext4_find_dest_de:2050: inode #12: block 7: comm syz.0.17: bad entry in directory: directory entry overrun - offset=0, inode=268435456, rec_len=1280, size=56 fake=0
DEBUG: inode 12: ext4_xattr_ibody_get called, EXT4_STATE_XATTR is set
DEBUG: inode 12: ibody_get IFIRST=ffff88806edbd004 end=ffff88806edbd000 gap=-4
==================================================================
BUG: KASAN: use-after-free in xattr_find_entry+0x1a5/0x280 fs/ext4/xattr.c:337
Read of size 4 at addr ffff88806edbd004 by task syz.0.17/6418
CPU: 0 UID: 49663 PID: 6418 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xba/0x230 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
xattr_find_entry+0x1a5/0x280 fs/ext4/xattr.c:337
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xba/0x230 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
ext4_xattr_ibody_get+0x314/0x560 fs/ext4/xattr.c:663
ext4_xattr_get+0x123/0x6a0 fs/ext4/xattr.c:717
ext4_get_acl+0x84/0x930 fs/ext4/acl.c:165
__get_acl+0x27e/0x410 fs/posix_acl.c:159
check_acl+0x3a/0x150 fs/namei.c:385
acl_permission_check fs/namei.c:471 [inline]
generic_permission+0x497/0x690 fs/namei.c:524
do_inode_permission fs/namei.c:585 [inline]
inode_permission+0x243/0x5f0 fs/namei.c:648
lookup_inode_permission_may_exec fs/namei.c:-1 [inline]
may_lookup fs/namei.c:1973 [inline]
link_path_walk+0x1149/0x18d0 fs/namei.c:2595
path_lookupat+0xe4/0x8c0 fs/namei.c:2803
filename_lookup+0x256/0x5d0 fs/namei.c:2833
user_path_at+0x40/0x160 fs/namei.c:3612
do_mount fs/namespace.c:4169 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x2dc/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fda1a19c629
__get_acl+0x27e/0x410 fs/posix_acl.c:159
check_acl+0x3a/0x150 fs/namei.c:385
acl_permission_check fs/namei.c:471 [inline]
generic_permission+0x497/0x690 fs/namei.c:524
do_inode_permission fs/namei.c:585 [inline]
inode_permission+0x243/0x5f0 fs/namei.c:648
lookup_inode_permission_may_exec fs/namei.c:-1 [inline]
may_lookup fs/namei.c:1973 [inline]
link_path_walk+0x1149/0x18d0 fs/namei.c:2595
path_lookupat+0xe4/0x8c0 fs/namei.c:2803
filename_lookup+0x256/0x5d0 fs/namei.c:2833
user_path_at+0x40/0x160 fs/namei.c:3612
do_mount fs/namespace.c:4169 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x2dc/0x420 fs/namespace.c:4338
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fda1b0a4028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fda1a415fa0 RCX: 00007fda1a19c629
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000000
RBP: 00007fda1a232b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002094080 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda1a416038 R14: 00007fda1a415fa0 R15: 00007ffe64a91a68
</TASK>
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7f26dbd9c pfn:0x6edbd
The buggy address belongs to the physical page:
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001bb6008 ffffea0001bb8dc8 0000000000000000
raw: 00000007f26dbd9c 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 6414, tgid 6414 (rm), ts 151550332214, free_ts 151570996513
page_owner tracks the page as freed
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2484
folio_alloc_mpol_noprof mm/mempolicy.c:2503 [inline]
vma_alloc_folio_noprof+0xea/0x210 mm/mempolicy.c:2538
folio_prealloc mm/memory.c:-1 [inline]
alloc_anon_folio mm/memory.c:5209 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2484
folio_alloc_mpol_noprof mm/mempolicy.c:2503 [inline]
vma_alloc_folio_noprof+0xea/0x210 mm/mempolicy.c:2538
folio_prealloc mm/memory.c:-1 [inline]
do_anonymous_page mm/memory.c:5266 [inline]
do_pte_missing+0x1656/0x3490 mm/memory.c:4475
handle_pte_fault mm/memory.c:6317 [inline]
__handle_mm_fault mm/memory.c:6455 [inline]
handle_mm_fault+0x1bec/0x3310 mm/memory.c:6624
do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
page last free pid 6414 tgid 6414 stack trace:
__handle_mm_fault mm/memory.c:6455 [inline]
handle_mm_fault+0x1bec/0x3310 mm/memory.c:6624
do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
free_unref_folios+0xed5/0x16d0 mm/page_alloc.c:3040
folios_put_refs+0x789/0x8d0 mm/swap.c:1002
free_pages_and_swap_cache+0x2e7/0x5b0 mm/swap_state.c:423
__tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:398 [inline]
tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:405
tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:530
exit_mmap+0x498/0xa10 mm/mmap.c:1315
__mmput+0x118/0x430 kernel/fork.c:1175
exit_mm+0x168/0x220 kernel/exit.c:581
do_exit+0x6a2/0x23c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1118
__do_sys_exit_group kernel/exit.c:1129 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
free_unref_folios+0xed5/0x16d0 mm/page_alloc.c:3040
folios_put_refs+0x789/0x8d0 mm/swap.c:1002
free_pages_and_swap_cache+0x2e7/0x5b0 mm/swap_state.c:423
__tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:398 [inline]
tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:405
tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:530
exit_mmap+0x498/0xa10 mm/mmap.c:1315
__mmput+0x118/0x430 kernel/fork.c:1175
exit_mm+0x168/0x220 kernel/exit.c:581
do_exit+0x6a2/0x23c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1118
__se_sys_exit_group kernel/exit.c:1127 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1127
x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88806edbcf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88806edbcf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88806edbd000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88806edbd080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806edbd100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
Tested on:
commit: 46b51325 Merge tag 'v7.0-rc5-smb3-client-fix' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=173a9848580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b643133b3e44c9fd
dashboard link: https://syzkaller.appspot.com/bug?extid=fb32afec111a7d61b939
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=175a4eda580000
dashboard link: https://syzkaller.appspot.com/bug?extid=fb32afec111a7d61b939
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syzbot
Mar 29, 2026, 10:41:04 PM (21 hours ago) Mar 29
to karti...@gmail.com, linux-...@vger.kernel.org, syzkall...@googlegroups.com, ty...@mit.edu
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+fb32af...@syzkaller.appspotmail.com
Tested-by: syzbot+fb32af...@syzkaller.appspotmail.com
Tested on:
commit: 7aaa8047 Linux 7.0-rc6
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11487cca580000
Note: testing is done by a robot and is best-effort only.
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+fb32af...@syzkaller.appspotmail.com
Tested-by: syzbot+fb32af...@syzkaller.appspotmail.com
Tested on:
commit: 7aaa8047 Linux 7.0-rc6
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11487cca580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b643133b3e44c9fd
dashboard link: https://syzkaller.appspot.com/bug?extid=fb32afec111a7d61b939
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=1243ff52580000
dashboard link: https://syzkaller.appspot.com/bug?extid=fb32afec111a7d61b939
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Note: testing is done by a robot and is best-effort only.
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