From: syzbot <syzbot+098999e05b6b877c01b3@syzkaller.appspotmail.com>
To: gregkh@linuxfoundation.org, khiemtranzo532001@gmail.com,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [usb?] KASAN: slab-use-after-free Write in pn_bind
Date: Sun, 11 Oct 2026 01:29:41 -0700 [thread overview]
Message-ID: <6acb48f5.bbc4c7f9.15faa7.007e.GAE@google.com> (raw)
In-Reply-To: <6a6d3a2e.6ce73036.24301b.0009.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: a5ebb76233b7 Merge tag 'edac_urgent_for_v7.3_rc7' of git:/..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=15860f15580000
kernel config: https://syzkaller.appspot.com/x/.config?x=df4bbab1c2172b9f
dashboard link: https://syzkaller.appspot.com/bug?extid=098999e05b6b877c01b3
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1506fc3e580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+098999e05b6b877c01b3@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in gphonet_set_gadget drivers/usb/gadget/function/f_phonet.c:720 [inline]
BUG: KASAN: slab-use-after-free in pn_bind+0x106/0xb20 drivers/usb/gadget/function/f_phonet.c:510
Write of size 8 at addr ffff888034f78900 by task syz.0.19/6513
CPU: 0 UID: 0 PID: 6513 Comm: syz.0.19 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
gphonet_set_gadget drivers/usb/gadget/function/f_phonet.c:720 [inline]
pn_bind+0x106/0xb20 drivers/usb/gadget/function/f_phonet.c:510
usb_add_function+0x290/0x930 drivers/usb/gadget/composite.c:333
configfs_composite_bind+0xde0/0x1410 drivers/usb/gadget/configfs.c:1802
gadget_bind_driver+0x2ca/0x9e0 drivers/usb/gadget/udc/core.c:1662
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x254/0xae0 drivers/base/dd.c:706
__driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
__driver_attach+0x339/0x600 drivers/base/dd.c:1292
bus_for_each_dev+0x23e/0x2c0 drivers/base/bus.c:383
bus_add_driver+0x348/0x670 drivers/base/bus.c:763
driver_register+0x23a/0x320 drivers/base/driver.c:174
usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1752
gadget_dev_desc_UDC_store+0x1c9/0x2f0 drivers/usb/gadget/configfs.c:300
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x33a/0x430 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61e/0xbb0 fs/read_write.c:687
ksys_write+0x156/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8b0ad5e0d9
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:00007f8b0a3be028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8b0afe5fa0 RCX: 00007f8b0ad5e0d9
RDX: 000000000000000b RSI: 0000200000000280 RDI: 0000000000000003
RBP: 00007f8b0a3be090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 00007f8b0afe6038 R14: 00007f8b0afe5fa0 R15: 00007ffddd2a1878
</TASK>
Allocated by task 6508:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:409 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5414 [inline]
__kvmalloc_node_noprof+0x5b4/0x890 mm/slub.c:7015
alloc_netdev_mqs+0xa9/0x12c0 net/core/dev.c:12163
gphonet_setup_default drivers/usb/gadget/function/f_phonet.c:706 [inline]
phonet_alloc_inst+0xa4/0x190 drivers/usb/gadget/function/f_phonet.c:640
try_get_usb_function_instance drivers/usb/gadget/functions.c:28 [inline]
usb_get_function_instance+0xe3/0x2f0 drivers/usb/gadget/functions.c:44
function_make+0x127/0x360 drivers/usb/gadget/configfs.c:626
configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1369
vfs_mkdir+0x408/0x620 fs/namei.c:5439
filename_mkdirat+0x289/0x520 fs/namei.c:5472
__do_sys_mkdirat fs/namei.c:5493 [inline]
__se_sys_mkdirat+0x35/0x150 fs/namei.c:5490
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 6510:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:264 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2748 [inline]
slab_free mm/slub.c:6509 [inline]
kfree+0x1c5/0x6d0 mm/slub.c:6802
device_release+0xc4/0x1f0 drivers/base/core.c:-1
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x222/0x550 lib/kobject.c:737
gphonet_register_netdev drivers/usb/gadget/function/f_phonet.c:729 [inline]
pn_bind+0x131/0xb20 drivers/usb/gadget/function/f_phonet.c:511
usb_add_function+0x290/0x930 drivers/usb/gadget/composite.c:333
configfs_composite_bind+0xde0/0x1410 drivers/usb/gadget/configfs.c:1802
gadget_bind_driver+0x2ca/0x9e0 drivers/usb/gadget/udc/core.c:1662
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x254/0xae0 drivers/base/dd.c:706
__driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
__driver_attach+0x339/0x600 drivers/base/dd.c:1292
bus_for_each_dev+0x23e/0x2c0 drivers/base/bus.c:383
bus_add_driver+0x348/0x670 drivers/base/bus.c:763
driver_register+0x23a/0x320 drivers/base/driver.c:174
usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1752
gadget_dev_desc_UDC_store+0x1c9/0x2f0 drivers/usb/gadget/configfs.c:300
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x33a/0x430 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61e/0xbb0 fs/read_write.c:687
ksys_write+0x156/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff888034f78000
which belongs to the cache kmalloc-cg-8k of size 8192
The buggy address is located 2304 bytes inside of
freed 8192-byte region [ffff888034f78000, ffff888034f7a000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34f78
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888034f7a011
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813ff08640 dead000000000100 dead000000000122
raw: 0000000000000000 0000000300020002 00000000f5000000 ffff888034f7a011
head: 0080000000000040 ffff88813ff08640 dead000000000100 dead000000000122
head: 0000000000000000 0000000300020002 00000000f5000000 ffff888034f7a011
head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd60c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 72, tgid 72 (kworker/u8:4), ts 112596841346
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x2591/0x2600 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x230/0x5c0 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab+0x7d/0x620 mm/slub.c:3462
new_slab mm/slub.c:3513 [inline]
refill_objects+0x2d8/0x350 mm/slub.c:7418
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x339/0x690 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
__do_kmalloc_node mm/slub.c:5413 [inline]
__kvmalloc_node_noprof+0x6f4/0x890 mm/slub.c:7015
alloc_netdev_mqs+0xa9/0x12c0 net/core/dev.c:12163
nsim_create+0x87/0x1160 drivers/net/netdevsim/netdev.c:1136
__nsim_dev_port_add+0x7f8/0xcd0 drivers/net/netdevsim/dev.c:1434
nsim_dev_port_add_all+0x37/0xf0 drivers/net/netdevsim/dev.c:1495
nsim_dev_reload_create drivers/net/netdevsim/dev.c:1547 [inline]
nsim_dev_reload_up+0x4dd/0x880 drivers/net/netdevsim/dev.c:983
devlink_reload+0x4bb/0x890 net/devlink/dev.c:475
devlink_pernet_pre_exit+0x1ff/0x420 net/devlink/core.c:584
ops_pre_exit_list net/core/net_namespace.c:161 [inline]
ops_undo_list+0x17d/0x8d0 net/core/net_namespace.c:235
cleanup_net+0x575/0x810 net/core/net_namespace.c:706
page last free pid 5849 tgid 5849 ts 110263695073 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0xf8e/0x1070 mm/page_alloc.c:2962
__slab_free+0x250/0x2a0 mm/slub.c:5823
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_noprof+0x360/0x690 mm/slub.c:5010
vm_area_dup+0x28/0x750 mm/vma_init.c:128
__split_vma+0x1d7/0xa00 mm/vma.c:560
vms_gather_munmap_vmas+0x322/0x1370 mm/vma.c:1507
do_vmi_align_munmap+0x2c7/0x4d0 mm/vma.c:1675
do_vmi_munmap+0x252/0x2d0 mm/vma.c:1732
__vm_munmap+0x241/0x3e0 mm/vma.c:3415
__do_sys_munmap mm/mmap.c:1094 [inline]
__se_sys_munmap mm/mmap.c:1091 [inline]
__x64_sys_munmap+0x60/0x70 mm/mmap.c:1091
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff888034f78800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888034f78880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888034f78900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888034f78980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888034f78a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
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.
next prev parent reply other threads:[~2026-10-11 8:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-01 0:13 [syzbot] [usb?] KASAN: slab-use-after-free Write in pn_bind syzbot
2026-08-18 7:33 ` syzbot
2026-10-11 8:29 ` syzbot [this message]
2026-10-11 21:47 ` syzbot
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