KASAN: invalid-free in f_uac2_opts_c_srate_store

Status: upstream: reported C repro on 2026/08/12 11:26
Reported-by: syzbot+b6a7bd0aaf02331c6ebb@syzkaller.appspotmail.com
First crash: 2d03h, last: 2d02h
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 KASAN: invalid-free in f_uac2_opts_c_srate_store 24 syz, C 7 4d12h 14d 0/1 premoderation: reported C repro on 2026/07/31 06:11
upstream KASAN: invalid-free in f_uac2_opts_c_srate_store usb prio:normal 24 syz, C error 69 9h44m 16d 0/29 upstream: reported C repro on 2026/07/29 05:27

Sample crash report:
==================================================================
BUG: KASAN: invalid-free in slab_free mm/slub.c:3712 [inline]
BUG: KASAN: invalid-free in __kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
Free of addr ffff88810e605f4c by task syz-executor308/305

CPU: 1 PID: 305 Comm: syz-executor308 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report_invalid_free+0xd5/0xf0 mm/kasan/report.c:489
 ____kasan_slab_free+0x14f/0x180 mm/kasan/common.c:-1
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
 kasan_slab_free include/linux/kasan.h:178 [inline]
 slab_free_hook mm/slub.c:1750 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
 slab_free mm/slub.c:3712 [inline]
 __kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
 kfree+0x6f/0xf0 mm/slab_common.c:990
 f_uac2_opts_c_srate_store+0x220/0x2a0 drivers/usb/gadget/function/f_uac2.c:2082
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x323/0x410 fs/configfs/file.c:229
 call_write_iter include/linux/fs.h:2282 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x5ef/0xd00 fs/read_write.c:584
 ksys_write+0x14a/0x260 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:646
 x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f985a20ccf9
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:00007fffbc715528 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 666e6f63796d2f2e RCX: 00007f985a20ccf9
RDX: 000000000000001a RSI: 00002000000004c0 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 00007fffbc715658
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffbc715648
R13: 0000000000000002 R14: 00007f985a29dca0 R15: 0000000000000002
 </TASK>

Allocated by task 305:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:380 [inline]
 __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:212 [inline]
 __do_kmalloc_node mm/slab_common.c:938 [inline]
 __kmalloc_node_track_caller+0xb1/0x1e0 mm/slab_common.c:958
 kstrdup+0x3b/0x80 mm/util.c:66
 f_uac2_opts_c_srate_store+0x11a/0x2a0 drivers/usb/gadget/function/f_uac2.c:2082
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x323/0x410 fs/configfs/file.c:229
 call_write_iter include/linux/fs.h:2282 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x5ef/0xd00 fs/read_write.c:584
 ksys_write+0x14a/0x260 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:646
 x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88810e605f40
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 12 bytes inside of
 32-byte region [ffff88810e605f40, ffff88810e605f60)

The buggy address belongs to the physical page:
page:ffffea0004398140 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e605
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 dead000000000001 ffff888100042600
raw: 0000000000000000 0000000080400040 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, tgid 1 (swapper/0), ts 3095057620, free_ts 0
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2679
 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4586
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5930
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3e0 mm/slub.c:2020
 ___slab_alloc+0x70f/0xb70 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 __kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
 __do_kmalloc_node mm/slab_common.c:937 [inline]
 __kmalloc+0xa4/0x1e0 mm/slab_common.c:951
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 kobject_get_path+0xbf/0x200 lib/kobject.c:152
 kobject_uevent_env+0x29f/0x720 lib/kobject_uevent.c:544
 kobject_uevent+0x1d/0x30 lib/kobject_uevent.c:657
 device_add+0xa1a/0xec0 drivers/base/core.c:3679
 device_create_groups_vargs drivers/base/core.c:4392 [inline]
 device_create_with_groups+0x26d/0x300 drivers/base/core.c:4478
 misc_register+0x250/0x470 drivers/char/misc.c:210
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88810e605e00: fb fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff88810e605e80: fb fb fb fb fc fc fc fc 00 00 00 02 fc fc fc fc
>ffff88810e605f00: fb fb fb fb fc fc fc fc 00 00 00 03 fc fc fc fc
                                              ^
 ffff88810e605f80: fb fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff88810e606000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/12 12:24 android14-6.1 92668decd5e0 f8d35649 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: invalid-free in f_uac2_opts_c_srate_store
2026/08/12 11:53 android14-6.1 92668decd5e0 f8d35649 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: invalid-free in f_uac2_opts_c_srate_store
2026/08/12 11:24 android14-6.1 92668decd5e0 f8d35649 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: invalid-free in f_uac2_opts_c_srate_store
2026/08/12 10:51 android14-6.1 92668decd5e0 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: invalid-free in f_uac2_opts_c_srate_store
* Struck through repros no longer work on HEAD.