syzbot


KASAN: invalid-free in free_prealloced_shrinker

Status: fixed on 2023/02/24 13:50
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+8b481578352d4637f510@syzkaller.appspotmail.com
Fix commit: 14773bfa70e6 mm: shrinkers: fix double kfree on shrinker name
First crash: 645d, last: 645d
Cause bisection: introduced by (bisect log) :
commit bec0918551a79c3c6b63a493a80e35e8b402804f
Author: Roman Gushchin <roman.gushchin@linux.dev>
Date: Wed Jun 1 03:22:24 2022 +0000

  mm: shrinkers: provide shrinkers with names

Crash: KASAN: invalid-free in free_prealloced_shrinker (log)
Repro: C syz .config
  
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] mm: shrinkers: fix double kfree on shrinker name 2 (2) 2022/07/20 16:29
[syzbot] KASAN: invalid-free in free_prealloced_shrinker 0 (1) 2022/07/20 07:52

Sample crash report:
==================================================================
BUG: KASAN: double-free in slab_free mm/slub.c:3534 [inline]
BUG: KASAN: double-free in kfree+0xe2/0x4d0 mm/slub.c:4562

CPU: 0 PID: 3647 Comm: syz-executor232 Not tainted 5.19.0-rc4-next-20220628-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:317 [inline]
 print_report.cold+0x2ba/0x719 mm/kasan/report.c:433
 kasan_report_invalid_free+0x8f/0x1a0 mm/kasan/report.c:462
 ____kasan_slab_free+0x18b/0x1c0 mm/kasan/common.c:355
 kasan_slab_free include/linux/kasan.h:200 [inline]
 slab_free_hook mm/slub.c:1754 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1780
 slab_free mm/slub.c:3534 [inline]
 kfree+0xe2/0x4d0 mm/slub.c:4562
 kfree_const+0x51/0x60 mm/util.c:41
 free_prealloced_shrinker+0x32/0x160 mm/vmscan.c:658
 destroy_unused_super.part.0+0x106/0x170 fs/super.c:185
 destroy_unused_super fs/super.c:278 [inline]
 alloc_super+0x8bd/0xaa0 fs/super.c:277
 sget_fc+0x13e/0x7c0 fs/super.c:530
 vfs_get_super fs/super.c:1134 [inline]
 get_tree_nodev+0x24/0x1d0 fs/super.c:1169
 vfs_get_tree+0x89/0x2f0 fs/super.c:1501
 do_new_mount fs/namespace.c:3040 [inline]
 path_mount+0x1320/0x1fa0 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f84280f4ef9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 15 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc55338338 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f84280f4ef9
RDX: 00000000200000c0 RSI: 0000000020000080 RDI: 0000000000000000
RBP: 00007ffc55338360 R08: 0000000000000000 R09: 00007ffc55338370
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ffc55338380 R14: 00007ffc553383c0 R15: 0000000000000006
 </TASK>

Allocated by task 143:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:436 [inline]
 ____kasan_kmalloc mm/kasan/common.c:515 [inline]
 ____kasan_kmalloc mm/kasan/common.c:474 [inline]
 __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524
 kmalloc include/linux/slab.h:605 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 rh_call_control drivers/usb/core/hcd.c:514 [inline]
 rh_urb_enqueue drivers/usb/core/hcd.c:848 [inline]
 usb_hcd_submit_urb+0x661/0x2220 drivers/usb/core/hcd.c:1551
 usb_submit_urb+0x86d/0x1880 drivers/usb/core/urb.c:594
 usb_start_wait_urb+0x101/0x4b0 drivers/usb/core/message.c:58
 usb_internal_control_msg drivers/usb/core/message.c:102 [inline]
 usb_control_msg+0x31c/0x4a0 drivers/usb/core/message.c:153
 get_port_status drivers/usb/core/hub.c:580 [inline]
 hub_ext_port_status+0x112/0x450 drivers/usb/core/hub.c:597
 usb_hub_port_status drivers/usb/core/hub.c:619 [inline]
 hub_activate+0xa5c/0x1c90 drivers/usb/core/hub.c:1129
 process_one_work+0x991/0x1610 kernel/workqueue.c:2289
 worker_thread+0x665/0x1080 kernel/workqueue.c:2436
 kthread+0x2e9/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302

Freed by task 3647:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:45
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free+0x166/0x1c0 mm/kasan/common.c:328
 kasan_slab_free include/linux/kasan.h:200 [inline]
 slab_free_hook mm/slub.c:1754 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1780
 slab_free mm/slub.c:3534 [inline]
 kfree+0xe2/0x4d0 mm/slub.c:4562
 kfree_const+0x51/0x60 mm/util.c:41
 prealloc_shrinker+0x179/0x1b0 mm/vmscan.c:644
 alloc_super+0x831/0xaa0 fs/super.c:268
 sget_fc+0x13e/0x7c0 fs/super.c:530
 vfs_get_super fs/super.c:1134 [inline]
 get_tree_nodev+0x24/0x1d0 fs/super.c:1169
 vfs_get_tree+0x89/0x2f0 fs/super.c:1501
 do_new_mount fs/namespace.c:3040 [inline]
 path_mount+0x1320/0x1fa0 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

The buggy address belongs to the object at ffff888147889b20
 which belongs to the cache kmalloc-16 of size 16
The buggy address is located 0 bytes inside of
 16-byte region [ffff888147889b20, ffff888147889b30)

The buggy address belongs to the physical page:
page:ffffea00051e2240 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147889
flags: 0x57ff00000000200(slab|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000200 ffffea00051e2ac0 dead000000000002 ffff8880118413c0
raw: 0000000000000000 0000000080800080 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, tgid 1 (swapper/0), ts 8392902276, free_ts 0
 prep_new_page mm/page_alloc.c:2535 [inline]
 get_page_from_freelist+0x210d/0x3a30 mm/page_alloc.c:4282
 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5506
 alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2113
 alloc_pages+0x2b1/0x310 mm/mempolicy.c:2275
 alloc_slab_page mm/slub.c:1824 [inline]
 allocate_slab+0x27e/0x3d0 mm/slub.c:1969
 new_slab mm/slub.c:2029 [inline]
 ___slab_alloc+0x89d/0xef0 mm/slub.c:3031
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118
 slab_alloc_node mm/slub.c:3209 [inline]
 slab_alloc mm/slub.c:3251 [inline]
 __kmalloc_track_caller+0x382/0x430 mm/slub.c:4924
 kstrdup+0x36/0x70 mm/util.c:61
 kstrdup_const+0x53/0x80 mm/util.c:84
 __kernfs_new_node+0x9d/0x8b0 fs/kernfs/dir.c:589
 kernfs_new_node+0x93/0x120 fs/kernfs/dir.c:655
 kernfs_create_link+0xcb/0x230 fs/kernfs/symlink.c:39
 sysfs_do_create_link_sd+0x90/0x140 fs/sysfs/symlink.c:44
 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 sysfs_create_link+0x5f/0xc0 fs/sysfs/symlink.c:92
 driver_sysfs_add+0xf7/0x350 drivers/base/dd.c:412
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888147889a00: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
 ffff888147889a80: fb fb fc fc fb fb fc fc fb fb fc fc fb fb fc fc
>ffff888147889b00: fb fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
                               ^
 ffff888147889b80: 00 00 fc fc fa fb fc fc fa fb fc fc fa fb fc fc
 ffff888147889c00: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/07/19 08:13 linux-next cb71b93c2dc3 ff988920 .config strace log report syz C ci-upstream-linux-next-kasan-gce-root KASAN: invalid-free in free_prealloced_shrinker
2022/07/19 20:29 linux-next cb71b93c2dc3 72a3cc0c .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: invalid-free in free_prealloced_shrinker
2022/07/19 07:56 linux-next cb71b93c2dc3 ff988920 .config console log report info ci-upstream-linux-next-kasan-gce-root KASAN: invalid-free in free_prealloced_shrinker
* Struck through repros no longer work on HEAD.