syzbot


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

Status: upstream: reported on 2024/09/27 15:10
Subsystems: kernfs
[Documentation on labels]
Reported-by: syzbot+81380e5b57bacce8a9f6@syzkaller.appspotmail.com
First crash: 250d, last: 70d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernfs?] KASAN: slab-use-after-free Read in kernfs_add_one 0 (1) 2024/09/27 15:10
Similar bugs (6)
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 402d 1332d 0/28 auto-obsoleted due to no activity on 2024/08/14 07:44
linux-6.1 KASAN: use-after-free Read in kernfs_add_one (2) 1 392d 392d 0/3 auto-obsoleted due to no activity on 2024/07/29 04:04
linux-6.1 KASAN: use-after-free Read in kernfs_add_one (3) 1 284d 284d 0/3 auto-obsoleted due to no activity on 2024/11/13 12:08
linux-6.1 KASAN: use-after-free Read in kernfs_add_one (4) origin:upstream C 3 18h27m 145d 0/3 upstream: reported C repro on 2024/12/22 11:05
linux-6.1 KASAN: use-after-free Read in kernfs_add_one 1 699d 699d 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 595d 595d 0/3 auto-obsoleted due to no activity on 2024/01/09 18:18

Sample crash report:
usb 10-1: Direct firmware load for ueagle-atm/eagleII.fw failed with error -2
usb 10-1: Falling back to sysfs fallback for: ueagle-atm/eagleII.fw
==================================================================
BUG: KASAN: slab-use-after-free in kernfs_root fs/kernfs/kernfs-internal.h:70 [inline]
BUG: KASAN: slab-use-after-free in kernfs_add_one+0x27a/0x700 fs/kernfs/dir.c:818
Read of size 8 at addr ffff8880620dbd50 by task kworker/1:6/2202

CPU: 1 UID: 0 PID: 2202 Comm: kworker/1:6 Not tainted 6.14.0-rc5-syzkaller-00105-gf315296c92fd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events request_firmware_work_func
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x16e/0x5b0 mm/kasan/report.c:521
 kasan_report+0x143/0x180 mm/kasan/report.c:634
 kernfs_root fs/kernfs/kernfs-internal.h:70 [inline]
 kernfs_add_one+0x27a/0x700 fs/kernfs/dir.c:818
 kernfs_create_dir_ns+0xd9/0x120 fs/kernfs/dir.c:1071
 sysfs_create_dir_ns+0x189/0x3a0 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:73 [inline]
 kobject_add_internal+0x435/0x8d0 lib/kobject.c:240
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_add+0x152/0x220 lib/kobject.c:426
 class_dir_create_and_add drivers/base/core.c:3208 [inline]
 get_device_parent+0x391/0x410 drivers/base/core.c:3259
 device_add+0x325/0xbf0 drivers/base/core.c:3589
 fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:86 [inline]
 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:162 [inline]
 firmware_fallback_sysfs+0x307/0x9e0 drivers/base/firmware_loader/fallback.c:238
 _request_firmware+0xe55/0x1430 drivers/base/firmware_loader/main.c:941
 request_firmware_work_func+0x12a/0x280 drivers/base/firmware_loader/main.c:1194
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 2202:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4171
 __kernfs_new_node+0xd8/0x870 fs/kernfs/dir.c:624
 kernfs_new_node+0x137/0x240 fs/kernfs/dir.c:700
 kernfs_create_dir_ns+0x43/0x120 fs/kernfs/dir.c:1061
 sysfs_create_dir_ns+0x189/0x3a0 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:73 [inline]
 kobject_add_internal+0x435/0x8d0 lib/kobject.c:240
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_add+0x152/0x220 lib/kobject.c:426
 class_dir_create_and_add drivers/base/core.c:3208 [inline]
 get_device_parent+0x391/0x410 drivers/base/core.c:3259
 device_add+0x325/0xbf0 drivers/base/core.c:3589
 fw_load_sysfs_fallback drivers/base/firmware_loader/fallback.c:86 [inline]
 fw_load_from_user_helper drivers/base/firmware_loader/fallback.c:162 [inline]
 firmware_fallback_sysfs+0x307/0x9e0 drivers/base/firmware_loader/fallback.c:238
 _request_firmware+0xe55/0x1430 drivers/base/firmware_loader/main.c:941
 request_firmware_work_func+0x12a/0x280 drivers/base/firmware_loader/main.c:1194
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Freed by task 3498:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4609 [inline]
 kmem_cache_free+0x195/0x410 mm/slub.c:4711
 rcu_do_batch kernel/rcu/tree.c:2546 [inline]
 rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2802
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Last potentially related work creation:
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xaa/0xc0 mm/kasan/generic.c:548
 __call_rcu_common kernel/rcu/tree.c:3065 [inline]
 call_rcu+0x168/0xac0 kernel/rcu/tree.c:3172
 kernfs_put+0x1dc/0x370 fs/kernfs/dir.c:578
 __kernfs_remove+0x768/0x870 fs/kernfs/dir.c:1509
 kernfs_remove+0x7a/0xa0 fs/kernfs/dir.c:1529
 __kobject_del+0xe2/0x310 lib/kobject.c:604
 kobject_del+0x45/0x60 lib/kobject.c:627
 device_del+0x7ff/0x9b0 drivers/base/core.c:3874
 usb_disconnect+0x60b/0x950 drivers/usb/core/hub.c:2344
 hub_port_connect drivers/usb/core/hub.c:5373 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5673 [inline]
 port_event drivers/usb/core/hub.c:5833 [inline]
 hub_event+0x1ebc/0x5150 drivers/usb/core/hub.c:5915
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff8880620dbd20
 which belongs to the cache kernfs_node_cache of size 176
The buggy address is located 48 bytes inside of
 freed 176-byte region [ffff8880620dbd20, ffff8880620dbdd0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x620db
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff888140aaf000 ffffea0001609b00 dead000000000002
raw: 0000000000000000 0000000080110011 00000000f5000000 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 5849, tgid 5849 (syz-executor), ts 62666624823, free_ts 62638447352
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4739
 alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab+0x8f/0x3a0 mm/slub.c:2587
 new_slab mm/slub.c:2640 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3826
 __slab_alloc+0x58/0xa0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4171
 __kernfs_new_node+0xd8/0x870 fs/kernfs/dir.c:624
 kernfs_new_node+0x137/0x240 fs/kernfs/dir.c:700
 __kernfs_create_file+0x49/0x2e0 fs/kernfs/file.c:1034
 sysfs_add_file_mode_ns+0x24a/0x310 fs/sysfs/file.c:313
 create_files fs/sysfs/group.c:76 [inline]
 internal_create_group+0x782/0x12d0 fs/sysfs/group.c:183
 internal_create_groups fs/sysfs/group.c:223 [inline]
 sysfs_create_groups+0x56/0x120 fs/sysfs/group.c:249
 device_add_groups drivers/base/core.c:2812 [inline]
 device_add_attrs+0xe5/0x600 drivers/base/core.c:2876
 device_add+0x576/0xbf0 drivers/base/core.c:3619
page last free pid 0 tgid 0 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660
 pagetable_free include/linux/mm.h:2917 [inline]
 pagetable_dtor_free include/linux/mm.h:3015 [inline]
 __tlb_remove_table+0x33c/0x420 include/asm-generic/tlb.h:216
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x76/0xf0 mm/mmu_gather.c:282
 rcu_do_batch kernel/rcu/tree.c:2546 [inline]
 rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2802
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Memory state around the buggy address:
 ffff8880620dbc00: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
 ffff8880620dbc80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff8880620dbd00: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff8880620dbd80: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
 ffff8880620dbe00: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/07 10:44 upstream f315296c92fd 831e3629 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in kernfs_add_one
2024/12/03 02:13 upstream cdd30ebb1b9f bb326ffb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in kernfs_add_one
2024/11/15 18:41 upstream cfaaa7d010d1 f6ede3a3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in kernfs_add_one
2024/11/15 08:50 upstream cfaaa7d010d1 f6ede3a3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in kernfs_add_one
2024/10/31 21:56 upstream 0fc810ae3ae1 96eb609f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in kernfs_add_one
2024/09/08 10:37 upstream d1f2d51b711a 9750182a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: slab-use-after-free Read in kernfs_add_one
* Struck through repros no longer work on HEAD.