KASAN: invalid-free in f_uac1_opts_c_srate_store

Status: upstream: reported C repro on 2026/09/10 09:00
Bug presence: origin:lts
[Documentation on labels]
Reported-by: syzbot+4db47e82f0066ee7b838@syzkaller.appspotmail.com
First crash: 5d02h, last: 5d02h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/09/12 lts (merge base) 25fcaef79489 C [report] KASAN: invalid-free in f_uac1_opts_c_srate_store
2026/09/12 upstream (ToT) 31a4327ffe2d C Didn't crash
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 KASAN: invalid-free in f_uac1_opts_c_srate_store 24 syz, C 6 15d 50d 0/1 premoderation: reported C repro on 2026/07/27 01:32
upstream KASAN: invalid-free in f_uac1_opts_c_srate_store prio:normal usb 24 syz, C 6 17d 44d 0/29 upstream: reported C repro on 2026/08/02 03:46

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 ffff88810fada693 by task syz-executor375/305

CPU: 0 PID: 305 Comm: syz-executor375 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_uac1_opts_c_srate_store+0x220/0x2a0 drivers/usb/gadget/function/f_uac1.c:1593
 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: 0033:0x7f07d6c22cf9
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:00007ffd16f6f268 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f07d6c22cf9
RDX: 0000000000000029 RSI: 0000200000000040 RDI: 0000000000000003
RBP: 6769666e6f632f2e R08: 0000000000000000 R09: 00000000000a8c88
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd16f6f398
R13: 0000000000000002 R14: 00007f07d6cb3ca0 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_uac1_opts_c_srate_store+0x11a/0x2a0 drivers/usb/gadget/function/f_uac1.c:1593
 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 ffff88810fada680
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 19 bytes inside of
 64-byte region [ffff88810fada680, ffff88810fada6c0)

The buggy address belongs to the physical page:
page:ffffea00043eb680 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10fada
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 ffffea0004388dc0 dead000000000003 ffff888100042780
raw: 0000000000000000 0000000080200020 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 81, tgid 81 (rcS), ts 5507695646, free_ts 5503364603
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2673
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2680
 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4587
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5931
 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]
 ext4_htree_store_dirent+0x8d/0x650 fs/ext4/dir.c:485
 htree_dirblock_to_tree+0x8cc/0xee0 fs/ext4/namei.c:1141
 ext4_htree_fill_tree+0x60f/0x10e0 fs/ext4/namei.c:1220
 ext4_dx_readdir fs/ext4/dir.c:608 [inline]
 ext4_readdir+0x2d9f/0x3c10 fs/ext4/dir.c:145
 iterate_dir+0x26d/0x610 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0xf2/0x250 fs/readdir.c:354
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1581 [inline]
 free_pcp_prepare mm/page_alloc.c:1655 [inline]
 free_unref_page_prepare+0x81b/0x820 mm/page_alloc.c:3622
 free_unref_page+0x93/0x530 mm/page_alloc.c:3720
 free_the_page mm/page_alloc.c:863 [inline]
 __free_pages+0x67/0x100 mm/page_alloc.c:6021
 __vunmap+0xa3c/0xc00 mm/vmalloc.c:2739
 free_work+0x5a/0x80 mm/vmalloc.c:98
 process_one_work+0x717/0xc30 kernel/workqueue.c:2302
 worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
 kthread+0x281/0x320 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff88810fada580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88810fada600: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88810fada680: 00 00 00 00 00 02 fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff88810fada700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88810fada780: 00 00 00 00 00 00 00 00 fc fc fc fc

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/10 08:58 android14-6.1 945be0af8244 4e8b1cc6 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: invalid-free in f_uac1_opts_c_srate_store
* Struck through repros no longer work on HEAD.