KASAN: invalid-free in f_uac2_opts_p_srate_store

Status: upstream: reported C repro on 2026/08/01 22:27
Reported-by: syzbot+0a9828a0e2c091a9ca50@syzkaller.appspotmail.com
First crash: 7h47m, last: 6h10m
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: invalid-free in f_uac2_opts_p_srate_store usb prio:normal 24 syz, C error 37 6h26m 3d05h 0/29 upstream: reported C repro on 2026/07/30 00:09
android-6-12 KASAN: invalid-free in f_uac2_opts_p_srate_store 24 syz, C 5 2d20h 5d05h 0/1 premoderation: reported C repro on 2026/07/28 00:18

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 ffff88811e9ad918 by task syz-executor427/305

CPU: 1 PID: 305 Comm: syz-executor427 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_p_srate_store+0x220/0x2a0 drivers/usb/gadget/function/f_uac2.c:2078
 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: 0033:0x7f84a68e5ff9
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:00007ffe17feaac8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 73666769666e6f63 RCX: 00007f84a68e5ff9
RDX: 0000000000000055 RSI: 0000200000000340 RDI: 0000000000000003
RBP: 00007ffe17feaad8 R08: 00007f84a68cac10 R09: 00007f84a68cac10
R10: 00007f84a68cac10 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000002 R14: 00007f84a696dca0 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_p_srate_store+0x11a/0x2a0 drivers/usb/gadget/function/f_uac2.c:2078
 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 ffff88811e9ad900
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 24 bytes inside of
 96-byte region [ffff88811e9ad900, ffff88811e9ad960)

The buggy address belongs to the physical page:
page:ffffea00047a6b40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11e9ad
flags: 0x4000000000000200(slab|zone=1)
raw: 4000000000000200 0000000000000000 dead000000000122 ffff888100042900
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 197, tgid 197 (dhcpcd), ts 7415541182, free_ts 7190949742
 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_array include/linux/slab.h:615 [inline]
 check_load_and_stores net/core/filter.c:929 [inline]
 bpf_check_classic net/core/filter.c:1138 [inline]
 bpf_prepare_filter+0x645/0x11c0 net/core/filter.c:1331
 __get_filter+0x2e2/0x410 net/core/filter.c:1526
 sk_attach_filter+0x23/0x140 net/core/filter.c:1541
 sk_setsockopt+0x18b4/0x26b0 net/core/sock.c:1301
 sock_setsockopt+0x5a/0x70 net/core/sock.c:1552
 __sys_setsockopt+0x269/0x4e0 net/socket.c:2273
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1580 [inline]
 free_pcp_prepare mm/page_alloc.c:1654 [inline]
 free_unref_page_prepare+0x80c/0x820 mm/page_alloc.c:3621
 free_unref_page_list+0x117/0x8d0 mm/page_alloc.c:3772
 release_pages+0xc7e/0xce0 mm/swap.c:1053
 free_pages_and_swap_cache+0x86/0xa0 mm/swap_state.c:316
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu mm/mmu_gather.c:261 [inline]
 tlb_finish_mmu+0x1b2/0x380 mm/mmu_gather.c:361
 exit_mmap+0x41d/0xc10 mm/mmap.c:3384
 __mmput+0x92/0x340 kernel/fork.c:1319
 mmput+0x4b/0x150 kernel/fork.c:1343
 exit_mm kernel/exit.c:569 [inline]
 do_exit+0xa51/0x2850 kernel/exit.c:874
 do_group_exit+0x21b/0x2e0 kernel/exit.c:1030
 __do_sys_exit_group kernel/exit.c:1041 [inline]
 __se_sys_exit_group kernel/exit.c:1039 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1039
 x64_sys_call+0x7b4/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
 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

Memory state around the buggy address:
 ffff88811e9ad800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88811e9ad880: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff88811e9ad900:

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/01 23:18 android14-6.1 92668decd5e0 e611ffe1 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: invalid-free in f_uac2_opts_p_srate_store
2026/08/01 22:48 android14-6.1 92668decd5e0 e611ffe1 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: invalid-free in f_uac2_opts_p_srate_store
2026/08/01 22:16 android14-6.1 92668decd5e0 e611ffe1 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: invalid-free in f_uac2_opts_p_srate_store
2026/08/01 21:40 android14-6.1 92668decd5e0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: invalid-free in f_uac2_opts_p_srate_store
* Struck through repros no longer work on HEAD.