syzbot


KASAN: use-after-free Read in kernfs_add_one (2)

Status: upstream: reported on 2024/04/20 04:04
Reported-by: syzbot+52c455b925eb16d8864d@syzkaller.appspotmail.com
First crash: 60d, last: 60d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in kernfs_add_one kernfs C error inconclusive 39 70d 1000d 0/27 upstream: reported C repro on 2021/09/22 06:56
linux-6.1 KASAN: use-after-free Read in kernfs_add_one 1 367d 367d 0/3 auto-obsoleted due to no activity on 2023/09/26 01:13
linux-5.15 KASAN: use-after-free Read in kernfs_add_one 1 263d 263d 0/3 auto-obsoleted due to no activity on 2024/01/09 18:18

Sample crash report:
usb 1-1: Direct firmware load for ueagle-atm/adi930.fw failed with error -2
usb 1-1: Falling back to sysfs fallback for: ueagle-atm/adi930.fw
==================================================================
BUG: KASAN: use-after-free in kernfs_root fs/kernfs/kernfs-internal.h:66 [inline]
BUG: KASAN: use-after-free in kernfs_next_descendant_post fs/kernfs/dir.c:1313 [inline]
BUG: KASAN: use-after-free in kernfs_activate fs/kernfs/dir.c:1368 [inline]
BUG: KASAN: use-after-free in kernfs_add_one+0x4ae/0x850 fs/kernfs/dir.c:800
Read of size 8 at addr ffff888016faf688 by task kworker/1:6/3636

CPU: 1 PID: 3636 Comm: kworker/1:6 Not tainted 6.1.87-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events request_firmware_work_func
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:395
 kasan_report+0x136/0x160 mm/kasan/report.c:495
 kernfs_root fs/kernfs/kernfs-internal.h:66 [inline]
 kernfs_next_descendant_post fs/kernfs/dir.c:1313 [inline]
 kernfs_activate fs/kernfs/dir.c:1368 [inline]
 kernfs_add_one+0x4ae/0x850 fs/kernfs/dir.c:800
 kernfs_create_link+0x160/0x1f0 fs/kernfs/symlink.c:48
 sysfs_do_create_link_sd+0x85/0x100 fs/sysfs/symlink.c:44
 device_add_class_symlinks drivers/base/core.c:3415 [inline]
 device_add+0x6b5/0xfd0 drivers/base/core.c:3634
 fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:82 [inline]
 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:158 [inline]
 firmware_fallback_sysfs+0x2fd/0x940 drivers/base/firmware_loader/fallback.c:234
 _request_firmware+0xc13/0x1200 drivers/base/firmware_loader/main.c:856
 request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1105
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>

Allocated by task 3636:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737
 slab_alloc_node mm/slub.c:3398 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
 kmem_cache_zalloc include/linux/slab.h:682 [inline]
 __kernfs_new_node+0xd4/0x870 fs/kernfs/dir.c:608
 kernfs_new_node+0x136/0x230 fs/kernfs/dir.c:684
 kernfs_create_link+0xa1/0x1f0 fs/kernfs/symlink.c:39
 sysfs_do_create_link_sd+0x85/0x100 fs/sysfs/symlink.c:44
 device_add_class_symlinks drivers/base/core.c:3415 [inline]
 device_add+0x6b5/0xfd0 drivers/base/core.c:3634
 fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:82 [inline]
 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:158 [inline]
 firmware_fallback_sysfs+0x2fd/0x940 drivers/base/firmware_loader/fallback.c:234
 _request_firmware+0xc13/0x1200 drivers/base/firmware_loader/main.c:856
 request_firmware_work_func+0x126/0x270 drivers/base/firmware_loader/main.c:1105
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Freed by task 154:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1724 [inline]
 slab_free_freelist_hook mm/slub.c:1750 [inline]
 slab_free mm/slub.c:3661 [inline]
 kmem_cache_free+0x292/0x510 mm/slub.c:3683
 kernfs_put+0x325/0x4a0 fs/kernfs/dir.c:562
 __kernfs_remove+0x5fc/0x710 fs/kernfs/dir.c:1467
 kernfs_remove+0x76/0x90 fs/kernfs/dir.c:1487
 __kobject_del+0xe2/0x310 lib/kobject.c:596
 kobject_del+0x41/0x60 lib/kobject.c:619
 device_del+0x9fe/0xbd0 drivers/base/core.c:3896
 usb_disconnect+0x58f/0x8c0 drivers/usb/core/hub.c:2295
 hub_port_connect drivers/usb/core/hub.c:5309 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5605 [inline]
 port_event drivers/usb/core/hub.c:5761 [inline]
 hub_event+0x1f78/0x5730 drivers/usb/core/hub.c:5843
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 process_scheduled_works kernel/workqueue.c:2355 [inline]
 worker_thread+0xd04/0x1200 kernel/workqueue.c:2441
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

The buggy address belongs to the object at ffff888016faf658
 which belongs to the cache kernfs_node_cache of size 168
The buggy address is located 48 bytes inside of
 168-byte region [ffff888016faf658, ffff888016faf700)

The buggy address belongs to the physical page:
page:ffffea00005bebc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16faf
flags: 0xfff80000000200(slab|node=0|zone=1|lastcpupid=0xfff)
raw: 00fff80000000200 dead000000000100 dead000000000122 ffff888140009c80
raw: 0000000000000000 0000000080110011 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 3805, tgid 3805 (syz-executor.4), ts 86653843181, free_ts 86555785473
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2513
 prep_new_page mm/page_alloc.c:2520 [inline]
 get_page_from_freelist+0x31a1/0x3320 mm/page_alloc.c:4279
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5547
 alloc_slab_page+0x6a/0x150 mm/slub.c:1794
 allocate_slab mm/slub.c:1939 [inline]
 new_slab+0x84/0x2d0 mm/slub.c:1992
 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x1a5/0x2d0 mm/slub.c:3422
 kmem_cache_zalloc include/linux/slab.h:682 [inline]
 __kernfs_new_node+0xd4/0x870 fs/kernfs/dir.c:608
 kernfs_new_node+0x136/0x230 fs/kernfs/dir.c:684
 __kernfs_create_file+0x45/0x2e0 fs/kernfs/file.c:1043
 sysfs_add_file_mode_ns+0x246/0x300 fs/sysfs/file.c:294
 create_files fs/sysfs/group.c:64 [inline]
 internal_create_group+0x545/0xed0 fs/sysfs/group.c:148
 internal_create_groups fs/sysfs/group.c:188 [inline]
 sysfs_create_groups+0x52/0x110 fs/sysfs/group.c:214
 create_dir lib/kobject.c:68 [inline]
 kobject_add_internal+0x725/0xd10 lib/kobject.c:231
 kobject_add_varg lib/kobject.c:366 [inline]
 kobject_init_and_add+0x120/0x190 lib/kobject.c:449
 netdev_queue_add_kobject net/core/net-sysfs.c:1666 [inline]
 netdev_queue_update_kobjects+0x1f2/0x480 net/core/net-sysfs.c:1718
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1440 [inline]
 free_pcp_prepare mm/page_alloc.c:1490 [inline]
 free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3358
 free_unref_page_list+0x663/0x900 mm/page_alloc.c:3499
 release_pages+0x2836/0x2b40 mm/swap.c:1055
 __pagevec_release+0x80/0xf0 mm/swap.c:1075
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 truncate_inode_pages_range+0x48a/0x1340 mm/truncate.c:372
 kill_bdev block/bdev.c:76 [inline]
 blkdev_flush_mapping+0x154/0x2b0 block/bdev.c:664
 blkdev_put_whole block/bdev.c:695 [inline]
 blkdev_put+0x4c0/0x750 block/bdev.c:955
 deactivate_locked_super+0xa0/0x110 fs/super.c:332
 cleanup_mnt+0x490/0x520 fs/namespace.c:1186
 task_work_run+0x246/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff888016faf580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888016faf600: 00 00 00 fc fc fc fc fc fc fc fc fa fb fb fb fb
>ffff888016faf680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888016faf700: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff888016faf780: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/20 04:03 linux-6.1.y 6741e066ec76 af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in kernfs_add_one
* Struck through repros no longer work on HEAD.