KASAN: slab-use-after-free Write in ms_read_bytes

Status: upstream: reported on 2026/09/23 00:33
Subsystems: mmc
Labels: prio:high actionable
[Documentation on labels]
Reported-by: syzbot+ccffdf05833ebdaeae70@syzkaller.appspotmail.com
Fix commit: aa0a37b5024d memstick: core: wait for request completion before freeing card
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root]
First crash: 50d, last: 14d
▶ ▼ ✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision
999637e7 repro-c Reproduced: ✅ ❓ KASAN: slab-use-after-free Write in ms_read_bytes 2026/09/23 01:06 2026/09/23 01:15 2026/09/23 03:18 5207b90e
7c33f4b7 moderation Actionable: ✅ ❓ KASAN: slab-use-after-free Write in ms_read_bytes 2026/09/23 00:00 2026/09/23 00:00 2026/09/23 00:32 5207b90e
03dd2127 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: slab-use-after-free Write in ms_read_bytes 2026/09/19 00:00 2026/09/19 00:00 2026/09/19 00:33 853b104b
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH] memstick: core: wait for request completion before freeing card 2 (2) 2026/09/29 13:34
[PATCH] memstick: core: wait for request completion before freeing card 1 (1) 2026/09/24 20:41
[syzbot] [mmc?] KASAN: slab-use-after-free Write in ms_read_bytes 0 (1) 2026/09/23 00:33
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/09/23 03:18 13m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git c4e9f74da4389a6b3e505d329d99232915a6b9cd report job log log

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in ms_read_bytes+0x772/0xc70 drivers/memstick/host/rtsx_usb_ms.c:450
Write of size 1 at addr ffff8880777a1079 by task kworker/0:2/21098

CPU: 0 UID: 0 PID: 21098 Comm: kworker/0:2 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: events rtsx_usb_ms_handle_req
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
 ms_read_bytes+0x772/0xc70 drivers/memstick/host/rtsx_usb_ms.c:450
 rtsx_usb_ms_issue_cmd drivers/memstick/host/rtsx_usb_ms.c:477 [inline]
 rtsx_usb_ms_handle_req+0x345/0x1900 drivers/memstick/host/rtsx_usb_ms.c:531
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 20652:
 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]
 __kmalloc_cache_noprof+0x321/0x600 mm/slub.c:5563
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 memstick_alloc_card drivers/memstick/core/memstick.c:383 [inline]
 memstick_check+0x1a7/0x1250 drivers/memstick/core/memstick.c:452
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 20652:
 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+0x1c5/0x650 mm/slub.c:6802
 memstick_alloc_card drivers/memstick/core/memstick.c:420 [inline]
 memstick_check+0x7b6/0x1250 drivers/memstick/core/memstick.c:452
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880777a1000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 121 bytes inside of
 freed 2048-byte region [ffff8880777a1000, ffff8880777a1800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880777a2000 pfn:0x777a0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88801b042000 ffffea0000d22210 ffffea0000996c10
raw: ffff8880777a2000 0000000000080006 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff88801b042000 ffffea0000d22210 ffffea0000996c10
head: ffff8880777a2000 0000000000080006 00000000f5000000 0000000000000000
head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5692, tgid 5692 (kworker/0:4), ts 95201416730
 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+0x2209/0x2280 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x217/0x5a0 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+0x2d5/0x350 mm/slub.c:7418
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x2c8/0x6c0 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]
 __kmalloc_node_track_caller_noprof+0x548/0x720 mm/slub.c:5545
 kmalloc_reserve net/core/skbuff.c:637 [inline]
 __alloc_skb+0x2c1/0x7a0 net/core/skbuff.c:715
 alloc_skb include/linux/skbuff.h:1384 [inline]
 mld_newpack+0x165/0xcb0 net/ipv6/mcast.c:1810
 add_grhead net/ipv6/mcast.c:1921 [inline]
 add_grec+0x119f/0x19d0 net/ipv6/mcast.c:2060
 mld_send_initial_cr+0x288/0x550 net/ipv6/mcast.c:2305
 mld_dad_work+0x3d/0x480 net/ipv6/mcast.c:2331
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
page last free pid 9 tgid 9 ts 94893438601 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962
 __slab_free+0x274/0x2c0 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]
 __kmalloc_cache_noprof+0x29f/0x600 mm/slub.c:5559
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:547 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event+0xf37/0xa3a0 drivers/net/netdevsim/fib.c:889
 nsim_fib_event_work+0x244/0x3b0 drivers/net/netdevsim/fib.c:1493
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff8880777a0f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880777a0f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880777a1000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8880777a1080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880777a1100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (36):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/04 19:16 upstream 6addb4f38557 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/05 22:30 upstream 67f0943b394d 1995e6c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/27 12:28 upstream fd179f8a05be a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/24 05:37 upstream fe2ec83746e5 0a1606bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/23 15:05 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdf12cde3083 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/22 17:23 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdf12cde3083 b55fad29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/19 10:20 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bdf12cde3083 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/18 04:02 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 9cbbd0c18603 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/18 00:54 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 9cbbd0c18603 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/17 17:47 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 9cbbd0c18603 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/15 22:39 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/13 21:10 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 5a1eeac4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/10 12:57 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 648b08aa37c1 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/08 23:42 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 42bcac323cc3 b2734a59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/06 16:15 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 5926a7da8789 f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/04 15:54 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 639df5d23876 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/04 12:43 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 639df5d23876 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/03 17:29 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 639df5d23876 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/02 23:21 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 647f31f34d40 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/02 15:03 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 647f31f34d40 6d32eb1f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/10/01 22:25 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 647f31f34d40 f5cdae2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/30 17:33 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 7808aef4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/30 07:06 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 7808aef4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/29 19:54 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 328436b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/29 19:48 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 328436b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/29 11:51 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/28 11:00 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/26 15:26 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/24 11:42 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 0281b448 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/24 05:20 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 0281b448 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/24 05:16 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 0281b448 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/23 15:00 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c abce1216 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/21 15:20 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/20 06:59 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/19 04:18 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
2026/09/17 20:10 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d58dffe9ee2c 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Write in ms_read_bytes
* Struck through repros no longer work on HEAD.