KASAN: invalid-free in f_uac2_opts_p_srate_store

Status: premoderation: reported C repro on 2026/07/28 00:18
Reported-by: syzbot+98b3f872ff1e26f7551a@syzkaller.appspotmail.com
First crash: 2d23h, last: 14h25m
Similar bugs (1)
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 14 18h05m 23h12m 0/29 upstream: reported C repro on 2026/07/30 00:09

Sample crash report:
==================================================================
BUG: KASAN: invalid-free in f_uac2_opts_p_srate_store+0x224/0x2b0 drivers/usb/gadget/function/f_uac2.c:2087
Free of addr ffff888130d67d86 by task syz-executor413/313

CPU: 0 UID: 0 PID: 313 Comm: syz-executor413 Not tainted syzkaller #0 0b31bef96cff8e44f9e14c4f768eb06c85e3b290
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 print_address_description+0x71/0x210 mm/kasan/report.c:377
 print_report+0x4a/0x70 mm/kasan/report.c:481
 kasan_report_invalid_free+0x11e/0x160 mm/kasan/report.c:556
 check_slab_allocation+0xdf/0xf0 include/linux/page-flags.h:-1
 __kasan_slab_pre_free+0x36/0x50 mm/kasan/common.c:257
 kasan_slab_pre_free include/linux/kasan.h:199 [inline]
 slab_free_hook mm/slub.c:2390 [inline]
 slab_free mm/slub.c:4714 [inline]
 kfree+0xf8/0x440 mm/slub.c:4875
 f_uac2_opts_p_srate_store+0x224/0x2b0 drivers/usb/gadget/function/f_uac2.c:2087
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x32f/0x490 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x762/0xfd0 fs/read_write.c:684
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f5f6b1a7cb9
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:00007ffde87e8358 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f5f6b1a7cb9
RDX: 0000000000000020 RSI: 0000200000000040 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffde87e8488
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffde87e8478
R13: 0000000000000002 R14: 00007f5f6b238ca0 R15: 0000000000000002
 </TASK>

Allocated by task 313:
 kasan_save_stack mm/kasan/common.c:49 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
 kasan_save_alloc_info+0x3a/0x50 mm/kasan/generic.c:565
 poison_kmalloc_redzone mm/kasan/common.c:379 [inline]
 __kasan_kmalloc+0x96/0xb0 mm/kasan/common.c:396
 kasan_kmalloc include/linux/kasan.h:261 [inline]
 __do_kmalloc_node mm/slub.c:4395 [inline]
 __kmalloc_node_track_caller_noprof+0x24e/0x4f0 mm/slub.c:4414
 kstrdup+0x4d/0x130 mm/util.c:70
 f_uac2_opts_p_srate_store+0x11e/0x2b0 drivers/usb/gadget/function/f_uac2.c:2087
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x32f/0x490 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x762/0xfd0 fs/read_write.c:684
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

The buggy address belongs to the object at ffff888130d67d80
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 6 bytes inside of
 32-byte region [ffff888130d67d80, ffff888130d67da0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x130d67
flags: 0x4000000000000000(zone=1)
page_type: f5(slab)
raw: 4000000000000000 ffff888100041780 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080400040 00000001f5000000 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 313, tgid 313 (strace-static-x), ts 33000580009, free_ts 27035260638
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook+0x37d/0x3b0 mm/page_alloc.c:1863
 prep_new_page+0x2d/0x180 mm/page_alloc.c:1871
 get_page_from_freelist+0x4aea/0x4ba0 mm/page_alloc.c:3948
 __alloc_pages_noprof+0x35a/0x7e0 mm/page_alloc.c:5315
 alloc_slab_page+0x6b/0x1e0 mm/slub.c:-1
 allocate_slab+0x69/0x430 mm/slub.c:2687
 new_slab mm/slub.c:2741 [inline]
 ___slab_alloc+0x591/0x8c0 mm/slub.c:3934
 __slab_alloc mm/slub.c:4025 [inline]
 __slab_alloc_node mm/slub.c:4078 [inline]
 slab_alloc_node mm/slub.c:4239 [inline]
 __do_kmalloc_node mm/slub.c:4394 [inline]
 __kmalloc_noprof+0x2fc/0x510 mm/slub.c:4407
 kmalloc_noprof include/linux/slab.h:885 [inline]
 kzalloc_noprof include/linux/slab.h:1017 [inline]
 lsm_blob_alloc security/security.c:686 [inline]
 lsm_cred_alloc security/security.c:703 [inline]
 security_prepare_creds+0x66/0x260 security/security.c:3245
 prepare_creds+0x46d/0x6b0 kernel/cred.c:245
 prepare_exec_creds+0x1b/0x220 kernel/cred.c:264
 prepare_bprm_creds fs/exec.c:1517 [inline]
 bprm_execve+0xe8/0x13f0 fs/exec.c:1886
 do_execveat_common+0x97e/0xae0 fs/exec.c:2011
 do_execve fs/exec.c:2085 [inline]
 __do_sys_execve fs/exec.c:2161 [inline]
 __se_sys_execve fs/exec.c:2156 [inline]
 __x64_sys_execve+0x96/0xb0 fs/exec.c:2156
 x64_sys_call+0x12c4/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:60
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
page last free pid 299 tgid 299 stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1390 [inline]
 free_unref_page+0xbb8/0xf70 mm/page_alloc.c:2876
 __folio_put+0x272/0x2c0 mm/swap.c:115
 folio_put include/linux/mm.h:1589 [inline]
 put_page include/linux/mm.h:1661 [inline]
 anon_pipe_buf_release+0x169/0x1f0 fs/pipe.c:128
 pipe_buf_release include/linux/pipe_fs_i.h:219 [inline]
 pipe_update_tail fs/pipe.c:224 [inline]
 pipe_read+0x621/0x11d0 fs/pipe.c:344
 new_sync_read fs/read_write.c:489 [inline]
 vfs_read+0x60e/0xc70 fs/read_write.c:570
 ksys_read+0x145/0x260 fs/read_write.c:713
 __do_sys_read fs/read_write.c:723 [inline]
 __se_sys_read fs/read_write.c:721 [inline]
 __x64_sys_read+0x7f/0x90 fs/read_write.c:721
 x64_sys_call+0x2638/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Memory state around the buggy address:
 ffff888130d67c80: fa fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888130d67d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888130d67d80: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
                   ^
 ffff888130d67e00: fa fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888130d67e80: fa fb fb fb fc fc fc fc fc f

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/30 08:55 android16-6.12 f1c9c21d1c2f 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust KASAN: invalid-free in f_uac2_opts_p_srate_store
2026/07/29 19:27 android16-6.12 f1c9c21d1c2f 6ef5c1e2 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust KASAN: invalid-free in f_uac2_opts_p_srate_store
2026/07/29 18:50 android16-6.12 f1c9c21d1c2f 6ef5c1e2 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust KASAN: invalid-free in f_uac2_opts_p_srate_store
2026/07/30 04:52 android16-6.12 f1c9c21d1c2f 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust KASAN: invalid-free in f_uac2_opts_p_srate_store
2026/07/28 00:18 android16-6.12 a12ab5a23a35 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust KASAN: invalid-free in f_uac2_opts_p_srate_store
* Struck through repros no longer work on HEAD.