[Android 5.10] KASAN: use-after-free Read in seq_printf (3)
2 views
Skip to first unread message
syzbot
Oct 12, 2026, 3:47:40 PM (3 days ago) Oct 12
to syzkaller-a...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 437aef3f57e8 Revert "Bluetooth: btusb: Fix BD_ADDR byte or..
git tree: android13-5.10-lts
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1479a9c9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=57bdfa4a173e5087
dashboard link: https://syzkaller.appspot.com/bug?extid=3f14923befdff8a9f03c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11f83c21580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13f625d1580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0f14ff921c7/disk-437aef3f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f68b89132312/vmlinux-437aef3f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fd0b482a3bae/bzImage-437aef3f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3f1492...@syzkaller.appspotmail.com
printk: console [ttyS0] disabled
printk: console [ttyS0] enabled
==================================================================
BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:641 [inline]
BUG: KASAN: use-after-free in string+0x20f/0x2a0 lib/vsprintf.c:723
Read of size 1 at addr ffff888100dad4d8 by task syz-executor201/297
CPU: 1 PID: 297 Comm: syz-executor201 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
__dump_stack+0x21/0x24 lib/dump_stack.c:77
dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:435 [inline]
kasan_report+0x100/0x140 mm/kasan/report.c:452
__asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306
string_nocheck lib/vsprintf.c:641 [inline]
string+0x20f/0x2a0 lib/vsprintf.c:723
vsnprintf+0xec5/0x1990 lib/vsprintf.c:2689
seq_vprintf fs/seq_file.c:398 [inline]
seq_printf+0x185/0x280 fs/seq_file.c:413
show_interrupts+0x921/0xa90 kernel/irq/proc.c:526
seq_read_iter+0x908/0xce0 fs/seq_file.c:272
proc_reg_read_iter+0x1be/0x290 fs/proc/inode.c:310
call_read_iter include/linux/fs.h:2066 [inline]
generic_file_splice_read+0x3ea/0x5f0 fs/splice.c:311
do_splice_to fs/splice.c:791 [inline]
splice_direct_to_actor+0x40a/0xb20 fs/splice.c:870
do_splice_direct+0x1c2/0x2d0 fs/splice.c:979
do_sendfile+0x8df/0x1040 fs/read_write.c:1257
__do_sys_sendfile64 fs/read_write.c:1318 [inline]
__se_sys_sendfile64 fs/read_write.c:1304 [inline]
__x64_sys_sendfile64+0x199/0x1f0 fs/read_write.c:1304
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f424033cdf9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd99a43888 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 636f7270796d2f2e RCX: 00007f424033cdf9
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000007
RBP: 0000000000000001 R08: 00007ffd99a439c8 R09: 00007ffd99a439c8
R10: 00000000000007ff R11: 0000000000000246 R12: 00007ffd99a439b8
R13: 0000000000000002 R14: 00007f42403cdca0 R15: 0000200000000004
Allocated by task 0:
(stack is not available)
Freed by task 297:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
kasan_slab_free include/linux/kasan.h:220 [inline]
slab_free_hook mm/slub.c:1600 [inline]
slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626
slab_free mm/slub.c:3208 [inline]
kfree+0xc0/0x270 mm/slub.c:4196
uart_remove_one_port+0x3b8/0x780 drivers/tty/serial/serial_core.c:3104
serial8250_unregister_port+0xad/0x260 drivers/tty/serial/8250/8250_core.c:1156
serial_pnp_remove+0x6b/0x90 drivers/tty/serial/8250/8250_pnp.c:498
pnp_device_remove+0x75/0x250 drivers/pnp/driver.c:131
__device_release_driver drivers/base/dd.c:-1 [inline]
device_release_driver_internal+0x531/0x7c0 drivers/base/dd.c:1221
device_driver_detach+0x3b/0x40 drivers/base/dd.c:1257
unbind_store+0x2e5/0x300 drivers/base/bus.c:193
drv_attr_store+0x79/0xa0 drivers/base/bus.c:77
sysfs_kf_write+0x129/0x150 fs/sysfs/file.c:143
kernfs_fop_write_iter+0x2bd/0x400 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2072 [inline]
new_sync_write fs/read_write.c:518 [inline]
vfs_write+0x770/0xd70 fs/read_write.c:605
ksys_write+0x14a/0x260 fs/read_write.c:658
__do_sys_write fs/read_write.c:670 [inline]
__se_sys_write fs/read_write.c:667 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:667
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
The buggy address belongs to the object at ffff888100dad4d8
which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes inside of
8-byte region [ffff888100dad4d8, ffff888100dad4e0)
The buggy address belongs to the page:
page:ffffea0004036b40 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888100dadbe0 pfn:0x100dad
flags: 0x4000000000000200(slab)
raw: 4000000000000200 ffffea000411f7c0 0000000900000009 ffff888100043c80
raw: ffff888100dadbe0 0000000080660028 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 2058600849, free_ts 0
set_page_owner include/linux/page_owner.h:35 [inline]
post_alloc_hook mm/page_alloc.c:2456 [inline]
prep_new_page+0x176/0x190 mm/page_alloc.c:2462
get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254
__alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384
alloc_slab_page mm/slub.c:-1 [inline]
allocate_slab mm/slub.c:1813 [inline]
new_slab+0x84/0x3f0 mm/slub.c:1874
new_slab_objects mm/slub.c:2632 [inline]
___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796
__slab_alloc+0x63/0xa0 mm/slub.c:2836
slab_alloc_node mm/slub.c:2918 [inline]
slab_alloc mm/slub.c:2960 [inline]
__kmalloc+0x1f9/0x330 mm/slub.c:4034
kmalloc include/linux/slab.h:560 [inline]
acpi_os_allocate include/acpi/platform/aclinuxex.h:52 [inline]
acpi_ex_allocate_name_string drivers/acpi/acpica/exnames.c:66 [inline]
acpi_ex_get_name_string+0x5a9/0xca0 drivers/acpi/acpica/exnames.c:367
acpi_ds_create_operand+0x168/0x8b0 drivers/acpi/acpica/dsutils.c:446
acpi_ds_create_operands+0x271/0x410 drivers/acpi/acpica/dsutils.c:707
acpi_ds_eval_buffer_field_operands+0x67/0x300 drivers/acpi/acpica/dsopcode.c:290
acpi_ds_exec_end_op+0x98f/0x1190 drivers/acpi/acpica/dswexec.c:546
acpi_ps_parse_loop+0xbff/0x19f0 drivers/acpi/acpica/psloop.c:526
acpi_ps_parse_aml+0x214/0x9a0 drivers/acpi/acpica/psparse.c:475
acpi_ps_execute_method+0x681/0x7b0 drivers/acpi/acpica/psxface.c:190
acpi_ns_evaluate+0x650/0xa20 drivers/acpi/acpica/nseval.c:205
page_owner free stack trace missing
Memory state around the buggy address:
ffff888100dad380: fc fc fc fa fc fc fc fc fb fc fc fc fc fb fc fc
ffff888100dad400: fc fc fb fc fc fc fc fb fc fc fc fc fa fc fc fc
>ffff888100dad480: fc fb fc fc fc fc 00 fc fc fc fc fa fc fc fc fc
^
ffff888100dad500: 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc fb
ffff888100dad580: fc fc fc fc fb fc fc fc fc fb fc fc fc fc fb fc
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 437aef3f57e8 Revert "Bluetooth: btusb: Fix BD_ADDR byte or..
git tree: android13-5.10-lts
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1479a9c9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=57bdfa4a173e5087
dashboard link: https://syzkaller.appspot.com/bug?extid=3f14923befdff8a9f03c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11f83c21580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13f625d1580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0f14ff921c7/disk-437aef3f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f68b89132312/vmlinux-437aef3f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fd0b482a3bae/bzImage-437aef3f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3f1492...@syzkaller.appspotmail.com
printk: console [ttyS0] disabled
printk: console [ttyS0] enabled
==================================================================
BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:641 [inline]
BUG: KASAN: use-after-free in string+0x20f/0x2a0 lib/vsprintf.c:723
Read of size 1 at addr ffff888100dad4d8 by task syz-executor201/297
CPU: 1 PID: 297 Comm: syz-executor201 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
__dump_stack+0x21/0x24 lib/dump_stack.c:77
dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:435 [inline]
kasan_report+0x100/0x140 mm/kasan/report.c:452
__asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306
string_nocheck lib/vsprintf.c:641 [inline]
string+0x20f/0x2a0 lib/vsprintf.c:723
vsnprintf+0xec5/0x1990 lib/vsprintf.c:2689
seq_vprintf fs/seq_file.c:398 [inline]
seq_printf+0x185/0x280 fs/seq_file.c:413
show_interrupts+0x921/0xa90 kernel/irq/proc.c:526
seq_read_iter+0x908/0xce0 fs/seq_file.c:272
proc_reg_read_iter+0x1be/0x290 fs/proc/inode.c:310
call_read_iter include/linux/fs.h:2066 [inline]
generic_file_splice_read+0x3ea/0x5f0 fs/splice.c:311
do_splice_to fs/splice.c:791 [inline]
splice_direct_to_actor+0x40a/0xb20 fs/splice.c:870
do_splice_direct+0x1c2/0x2d0 fs/splice.c:979
do_sendfile+0x8df/0x1040 fs/read_write.c:1257
__do_sys_sendfile64 fs/read_write.c:1318 [inline]
__se_sys_sendfile64 fs/read_write.c:1304 [inline]
__x64_sys_sendfile64+0x199/0x1f0 fs/read_write.c:1304
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f424033cdf9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd99a43888 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 636f7270796d2f2e RCX: 00007f424033cdf9
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000007
RBP: 0000000000000001 R08: 00007ffd99a439c8 R09: 00007ffd99a439c8
R10: 00000000000007ff R11: 0000000000000246 R12: 00007ffd99a439b8
R13: 0000000000000002 R14: 00007f42403cdca0 R15: 0000200000000004
Allocated by task 0:
(stack is not available)
Freed by task 297:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
__kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
kasan_slab_free include/linux/kasan.h:220 [inline]
slab_free_hook mm/slub.c:1600 [inline]
slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626
slab_free mm/slub.c:3208 [inline]
kfree+0xc0/0x270 mm/slub.c:4196
uart_remove_one_port+0x3b8/0x780 drivers/tty/serial/serial_core.c:3104
serial8250_unregister_port+0xad/0x260 drivers/tty/serial/8250/8250_core.c:1156
serial_pnp_remove+0x6b/0x90 drivers/tty/serial/8250/8250_pnp.c:498
pnp_device_remove+0x75/0x250 drivers/pnp/driver.c:131
__device_release_driver drivers/base/dd.c:-1 [inline]
device_release_driver_internal+0x531/0x7c0 drivers/base/dd.c:1221
device_driver_detach+0x3b/0x40 drivers/base/dd.c:1257
unbind_store+0x2e5/0x300 drivers/base/bus.c:193
drv_attr_store+0x79/0xa0 drivers/base/bus.c:77
sysfs_kf_write+0x129/0x150 fs/sysfs/file.c:143
kernfs_fop_write_iter+0x2bd/0x400 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2072 [inline]
new_sync_write fs/read_write.c:518 [inline]
vfs_write+0x770/0xd70 fs/read_write.c:605
ksys_write+0x14a/0x260 fs/read_write.c:658
__do_sys_write fs/read_write.c:670 [inline]
__se_sys_write fs/read_write.c:667 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:667
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
The buggy address belongs to the object at ffff888100dad4d8
which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes inside of
8-byte region [ffff888100dad4d8, ffff888100dad4e0)
The buggy address belongs to the page:
page:ffffea0004036b40 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888100dadbe0 pfn:0x100dad
flags: 0x4000000000000200(slab)
raw: 4000000000000200 ffffea000411f7c0 0000000900000009 ffff888100043c80
raw: ffff888100dadbe0 0000000080660028 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 2058600849, free_ts 0
set_page_owner include/linux/page_owner.h:35 [inline]
post_alloc_hook mm/page_alloc.c:2456 [inline]
prep_new_page+0x176/0x190 mm/page_alloc.c:2462
get_page_from_freelist+0x225f/0x23f0 mm/page_alloc.c:4254
__alloc_pages_nodemask+0x29a/0x640 mm/page_alloc.c:5384
alloc_slab_page mm/slub.c:-1 [inline]
allocate_slab mm/slub.c:1813 [inline]
new_slab+0x84/0x3f0 mm/slub.c:1874
new_slab_objects mm/slub.c:2632 [inline]
___slab_alloc+0x2f8/0x4c0 mm/slub.c:2796
__slab_alloc+0x63/0xa0 mm/slub.c:2836
slab_alloc_node mm/slub.c:2918 [inline]
slab_alloc mm/slub.c:2960 [inline]
__kmalloc+0x1f9/0x330 mm/slub.c:4034
kmalloc include/linux/slab.h:560 [inline]
acpi_os_allocate include/acpi/platform/aclinuxex.h:52 [inline]
acpi_ex_allocate_name_string drivers/acpi/acpica/exnames.c:66 [inline]
acpi_ex_get_name_string+0x5a9/0xca0 drivers/acpi/acpica/exnames.c:367
acpi_ds_create_operand+0x168/0x8b0 drivers/acpi/acpica/dsutils.c:446
acpi_ds_create_operands+0x271/0x410 drivers/acpi/acpica/dsutils.c:707
acpi_ds_eval_buffer_field_operands+0x67/0x300 drivers/acpi/acpica/dsopcode.c:290
acpi_ds_exec_end_op+0x98f/0x1190 drivers/acpi/acpica/dswexec.c:546
acpi_ps_parse_loop+0xbff/0x19f0 drivers/acpi/acpica/psloop.c:526
acpi_ps_parse_aml+0x214/0x9a0 drivers/acpi/acpica/psparse.c:475
acpi_ps_execute_method+0x681/0x7b0 drivers/acpi/acpica/psxface.c:190
acpi_ns_evaluate+0x650/0xa20 drivers/acpi/acpica/nseval.c:205
page_owner free stack trace missing
Memory state around the buggy address:
ffff888100dad380: fc fc fc fa fc fc fc fc fb fc fc fc fc fb fc fc
ffff888100dad400: fc fc fb fc fc fc fc fb fc fc fc fc fa fc fc fc
>ffff888100dad480: fc fb fc fc fc fc 00 fc fc fc fc fa fc fc fc fc
^
ffff888100dad500: 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc fb
ffff888100dad580: fc fc fc fc fb fc fc fc fc fb fc fc fc fc fb fc
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
Reply all
Reply to author
Forward
0 new messages