KASAN: slab-use-after-free Read in update_io

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
14841dfa-63b9-4713-bd29-041dd248e471	moderation		💥	KASAN: slab-use-after-free Read in update_io_ticks (4)	2026/03/10 15:23	2026/03/10 15:23	2026/03/10 15:23	d16aa12f36812fd3c4bc5f61111b6678f99f6b6e+	unexpected git log output: "warning: unable to access '/root/.config/git/attributes': Permission denied\nwarning: unable to access '/root/.config/git/attributes': Permission denied\naf4e9ef3d78420feb8fe58cd9a1ab80c501b3c08\nuaccess: Fix scoped_user_read_access() for 'pointer to const'\ndavid.laight.linux@gmail.com\nDavid Laight\nMon Mar 2 13:27:51 2026 +0000\n1b37ac211a22d4c65aad1ae2da07f078197e7394\nMon Mar 2 09:24:32 2026 -0800\nIf a 'const struct foo __user ptr' is used for the address passed to\nscoped_user_read_access() then you get a warning/error\n\n uaccess.h:691:1: error: initialization discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers]\n\nfor the\n\n void __user _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl)\n\nassignment.\n\nFix by using 'auto' for both _tmpptr and the redeclaration of uptr.\nReplace the CLASS() with explicit __cleanup() functions on uptr.\n\nFixes: e497310b4ffb (\"uaccess: Provide scoped user access regions\")\nSigned-off-by: David Laight <david.laight.linux@gmail.com>\nReviewed-and-tested-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>\nSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>\n"

Kernel	Title	Rank 🛈	Count	Last	Reported	Patched	Status
upstream	KASAN: slab-use-after-free Read in update_io_ticks (2) block	19	2	457d	456d	0/29	auto-obsoleted due to no activity on 2025/03/20 05:19
upstream	KASAN: slab-use-after-free Read in update_io_ticks block	19	1	561d	557d	0/29	auto-obsoleted due to no activity on 2024/11/27 03:17
upstream	KASAN: slab-use-after-free Read in update_io_ticks (3) block	19	1	215d	211d	0/29	auto-obsoleted due to no activity on 2025/11/17 16:37

Kernel

Title

Rank 🛈

upstream

KASAN: slab-use-after-free Read in update_io_ticks (2) block

457d

456d

0/29

auto-obsoleted due to no activity on 2025/03/20 05:19

upstream

KASAN: slab-use-after-free Read in update_io_ticks block

561d

557d

0/29

auto-obsoleted due to no activity on 2024/11/27 03:17

upstream

KASAN: slab-use-after-free Read in update_io_ticks (3) block

215d

211d

0/29

auto-obsoleted due to no activity on 2025/11/17 16:37

I/O error, dev loop0, sector 50 op 0x0:(READ) flags 0x800000 phys_seg 1 prio class 2 ================================================================== BUG: KASAN: slab-use-after-free in update_io_ticks+0xa9/0x280 block/blk-core.c:1028 Read of size 8 at addr ffff888031f11728 by task kworker/u4:7/1040 CPU: 0 UID: 0 PID: 1040 Comm: kworker/u4:7 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: loop0 loop_workfn Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 update_io_ticks+0xa9/0x280 block/blk-core.c:1028 blk_account_io_done+0x18b/0x7b0 block/blk-mq.c:1082 __blk_mq_end_request_acct block/blk-mq.c:1156 [inline] __blk_mq_end_request+0x2ae/0x630 block/blk-mq.c:1162 lo_rw_aio_complete drivers/block/loop.c:337 [inline] lo_rw_aio+0xcde/0xf00 drivers/block/loop.c:409 do_req_filebacked drivers/block/loop.c:435 [inline] loop_handle_cmd drivers/block/loop.c:1925 [inline] loop_process_work+0x958/0x11a0 drivers/block/loop.c:1960 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> Allocated by task 4711: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4515 [inline] slab_alloc_node mm/slub.c:4844 [inline] kmem_cache_alloc_lru_noprof+0x2b8/0x640 mm/slub.c:4863 bdev_alloc_inode+0x29/0x90 block/bdev.c:380 alloc_inode+0x6a/0x1b0 fs/inode.c:347 new_inode+0x22/0x170 fs/inode.c:1185 bdev_alloc+0x26/0x380 block/bdev.c:477 add_partition+0x1c3/0x8e0 block/partitions/core.c:327 blk_add_partition block/partitions/core.c:565 [inline] blk_add_partitions block/partitions/core.c:634 [inline] bdev_disk_changed+0xbab/0x1550 block/partitions/core.c:694 blkdev_get_whole+0x380/0x510 block/bdev.c:764 bdev_open+0x31e/0xd30 block/bdev.c:973 bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1075 disk_scan_partitions+0x1c1/0x2c0 block/genhd.c:387 blkdev_common_ioctl+0x1ce4/0x3250 block/ioctl.c:719 blkdev_ioctl+0x528/0x740 block/ioctl.c:798 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 15: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2692 [inline] slab_free mm/slub.c:6143 [inline] kmem_cache_free+0x187/0x630 mm/slub.c:6273 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x870 kernel/softirq.c:622 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1063 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3131 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3251 destroy_inode fs/inode.c:402 [inline] evict+0x95b/0xb10 fs/inode.c:870 device_release+0x9e/0x1d0 drivers/base/core.c:-1 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x228/0x560 lib/kobject.c:737 bdev_disk_changed+0x292/0x1550 block/partitions/core.c:675 __loop_clr_fd drivers/block/loop.c:1164 [inline] lo_release+0x547/0x840 drivers/block/loop.c:1751 bdev_release+0x536/0x650 block/bdev.c:-1 blkdev_release+0x15/0x20 block/fops.c:705 __fput+0x44f/0xa70 fs/file_table.c:469 fput_close_sync+0x11f/0x240 fs/file_table.c:574 __do_sys_close fs/open.c:1509 [inline] __se_sys_close fs/open.c:1494 [inline] __x64_sys_close+0x7e/0x110 fs/open.c:1494 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888031f11700 which belongs to the cache bdev_cache of size 2776 The buggy address is located 40 bytes inside of freed 2776-byte region [ffff888031f11700, ffff888031f121d8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x31f10 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff888044b7b281 flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000040 ffff888030414b40 dead000000000122 0000000000000000 raw: 0000000000000000 00000008000b000b 00000000f5000000 ffff888044b7b281 head: 04fff00000000040 ffff888030414b40 dead000000000122 0000000000000000 head: 0000000000000000 00000008000b000b 00000000f5000000 ffff888044b7b281 head: 04fff00000000003 ffffea0000c7c401 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 Reclaimable, gfp_mask 0xd20d0(__GFP_RECLAIMABLE|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 15439559208, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3269 [inline] allocate_slab+0x77/0x660 mm/slub.c:3458 new_slab mm/slub.c:3516 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7153 refill_sheaf mm/slub.c:2818 [inline] __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4592 alloc_from_pcs mm/slub.c:4695 [inline] slab_alloc_node mm/slub.c:4829 [inline] kmem_cache_alloc_lru_noprof+0x37c/0x640 mm/slub.c:4863 bdev_alloc_inode+0x29/0x90 block/bdev.c:380 alloc_inode+0x6a/0x1b0 fs/inode.c:347 new_inode+0x22/0x170 fs/inode.c:1185 bdev_alloc+0x26/0x380 block/bdev.c:477 __alloc_disk_node+0x11d/0x5b0 block/genhd.c:1465 __blk_alloc_disk+0x105/0x1d0 block/genhd.c:1519 pmem_attach_disk+0x4d1/0xe10 drivers/nvdimm/pmem.c:509 nvdimm_bus_probe+0x331/0x6c0 drivers/nvdimm/bus.c:91 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x267/0xaf0 drivers/base/dd.c:661 page_owner free stack trace missing Memory state around the buggy address: ffff888031f11600: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff888031f11680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888031f11700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888031f11780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888031f11800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/03/03 12:17	upstream	af4e9ef3d784	28b83e23	.config	console log	report				[disk image (non-bootable)] [vmlinux] [kernel image]	ci-snapshot-upstream-root	KASAN: slab-use-after-free Read in update_io_ticks

Crashes (1):

Assets (help?)