From: syzbot <syzbot+e5e28c3e953b2eebb16e@syzkaller.appspotmail.com>
To: gregkh@linuxfoundation.org, johan@kernel.org,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [usb?] KASAN: slab-use-after-free Read in usa49_glocont_callback
Date: Sun, 16 Aug 2026 09:12:28 -0700 [thread overview]
Message-ID: <6a81e16c.f7a79266.2f965f.0016.GAE@google.com> (raw)
In-Reply-To: <6a7e6fb9.ec5dc6cc.21cb3f.00c0.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 3eb40771c00a Merge tag 'soc-fixes-7.2-3' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=146196c6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1d67342c314f228d
dashboard link: https://syzkaller.appspot.com/bug?extid=e5e28c3e953b2eebb16e
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158a5a79580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e5e28c3e953b2eebb16e@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in usa49_glocont_callback+0x232/0x260 drivers/usb/serial/keyspan.c:1045
Read of size 4 at addr ffff88801fe9c9b0 by task syz-executor414/6031
CPU: 0 UID: 0 PID: 6031 Comm: syz-executor414 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
usa49_glocont_callback+0x232/0x260 drivers/usb/serial/keyspan.c:1045
__usb_hcd_giveback_urb+0x38d/0x610 drivers/usb/core/hcd.c:1657
usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741
dummy_timer+0xdb2/0x36f0 drivers/usb/gadget/udc/dummy_hcd.c:2019
__run_hrtimer kernel/time/hrtimer.c:2032 [inline]
__hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096
hrtimer_run_softirq+0x17d/0x2c0 kernel/time/hrtimer.c:2113
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:console_flush_one_record+0xac3/0xe50 kernel/printk/printk.c:3270
Code: 00 e8 91 26 2a 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 df d1 21 00 48 85 ed 0f 85 d7 01 00 00 e8 31 d7 21 00 fb 4c 89 e8 <48> c1 e8 03 42 80 3c 38 00 0f 85 64 03 00 00 48 8b 0c 24 48 8b 6b
RSP: 0018:ffffc900034a7310 EFLAGS: 00000293
RAX: ffffffff8fbaca18 RBX: ffffffff8fbac9c0 RCX: ffffffff81e89c41
RDX: ffff88802bbd4a80 RSI: ffffffff81e89c4f RDI: ffff88802bbd4a80
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000d63
R13: ffffffff8fbaca18 R14: ffffc900034a7390 R15: dffffc0000000000
console_flush_all kernel/printk/printk.c:3343 [inline]
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0x103/0x260 kernel/printk/printk.c:3413
vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
dev_vprintk_emit+0x391/0x3e0 drivers/base/core.c:4996
dev_printk_emit+0xd2/0x10d drivers/base/core.c:5007
__dev_printk+0xcb/0x100 drivers/base/core.c:5019
_dev_info+0xef/0x127 drivers/base/core.c:5065
usb_serial_device_remove.cold+0x34/0xb8 drivers/usb/serial/bus.c:99
device_remove+0xcb/0x180 drivers/base/dd.c:616
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
device_del+0x376/0x9b0 drivers/base/core.c:3961
usb_serial_disconnect+0x21e/0x490 drivers/usb/serial/usb-serial.c:1195
usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:618 [inline]
device_remove+0x12a/0x180 drivers/base/dd.c:610
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
unbind_store+0xf8/0x110 drivers/base/bus.c:244
drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe5f5fe8e1e
Code: 08 0f 85 f5 e2 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08
RSP: 002b:00007fffdd685de8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555562386400 RCX: 00007fe5f5fe8e1e
RDX: 0000000000000007 RSI: 00007fffdd685f80 RDI: 0000000000000005
RBP: 00000013c52a7a0a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffdd685e70
R13: 0000000000000006 R14: 00007fffdd685f80 R15: 0000000000000004
</TASK>
Allocated by task 6031:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x2e5/0x6c0 mm/slub.c:5489
_kmalloc_noprof include/linux/slab.h:988 [inline]
_kzalloc_noprof include/linux/slab.h:1309 [inline]
keyspan_port_probe+0xbc/0xdd0 drivers/usb/serial/keyspan.c:2891
usb_serial_device_probe+0x106/0x3e0 drivers/usb/serial/bus.c:47
call_driver_probe drivers/base/dd.c:628 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:706
__driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
__device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
bus_probe_device+0x64/0x160 drivers/base/bus.c:620
device_add+0x121d/0x1970 drivers/base/core.c:3772
usb_serial_probe.cold+0x257e/0x29f8 drivers/usb/serial/usb-serial.c:1147
usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:628 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:706
__driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
device_driver_attach+0xd1/0x220 drivers/base/dd.c:1203
bind_store+0xf4/0x190 drivers/base/bus.c:267
drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 6031:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2677 [inline]
slab_free mm/slub.c:6377 [inline]
kfree+0x22b/0x6c0 mm/slub.c:6692
usb_serial_device_remove+0x146/0x1a0 drivers/usb/serial/bus.c:97
device_remove+0xcb/0x180 drivers/base/dd.c:616
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
device_del+0x376/0x9b0 drivers/base/core.c:3961
usb_serial_disconnect+0x21e/0x490 drivers/usb/serial/usb-serial.c:1195
usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:618 [inline]
device_remove+0x12a/0x180 drivers/base/dd.c:610
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
unbind_store+0xf8/0x110 drivers/base/bus.c:244
drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88801fe9c900
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 176 bytes inside of
freed 192-byte region [ffff88801fe9c900, ffff88801fe9c9c0)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1fe9c
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801c0423c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 2697413350, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
alloc_slab_page mm/slub.c:3266 [inline]
allocate_slab mm/slub.c:3380 [inline]
new_slab+0xa2/0x640 mm/slub.c:3426
refill_objects+0xe3/0x410 mm/slub.c:7310
refill_sheaf mm/slub.c:2804 [inline]
__pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
alloc_from_pcs mm/slub.c:4773 [inline]
slab_alloc_node mm/slub.c:4905 [inline]
__kmalloc_cache_node_noprof+0x542/0x6c0 mm/slub.c:5504
_kmalloc_node_noprof include/linux/slab.h:1193 [inline]
mempool_create_node_noprof+0xb9/0x1b0 mm/mempool.c:319
sg_pool_init+0x179/0x2b0 lib/sg_pool.c:158
do_one_initcall+0x11d/0x700 init/main.c:1347
do_initcall_level init/main.c:1409 [inline]
do_initcalls init/main.c:1425 [inline]
do_basic_setup init/main.c:1445 [inline]
kernel_init_freeable+0x6ea/0x7b0 init/main.c:1658
kernel_init+0x1f/0x1e0 init/main.c:1548
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing
Memory state around the buggy address:
ffff88801fe9c880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88801fe9c900: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801fe9c980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
^
ffff88801fe9ca00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88801fe9ca80: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
0: 00 e8 add %ch,%al
2: 91 xchg %eax,%ecx
3: 26 2a 00 es sub (%rax),%al
6: 9c pushf
7: 5d pop %rbp
8: 81 e5 00 02 00 00 and $0x200,%ebp
e: 31 ff xor %edi,%edi
10: 48 89 ee mov %rbp,%rsi
13: e8 df d1 21 00 call 0x21d1f7
18: 48 85 ed test %rbp,%rbp
1b: 0f 85 d7 01 00 00 jne 0x1f8
21: e8 31 d7 21 00 call 0x21d757
26: fb sti
27: 4c 89 e8 mov %r13,%rax
* 2a: 48 c1 e8 03 shr $0x3,%rax <-- trapping instruction
2e: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1)
33: 0f 85 64 03 00 00 jne 0x39d
39: 48 8b 0c 24 mov (%rsp),%rcx
3d: 48 rex.W
3e: 8b .byte 0x8b
3f: 6b .byte 0x6b
---
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.
prev parent reply other threads:[~2026-08-16 16:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-14 1:30 [syzbot] [usb?] KASAN: slab-use-after-free Read in usa49_glocont_callback syzbot
2026-08-16 16:12 ` syzbot [this message]
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