syzbot


KASAN: use-after-free Read in __cgroup_bpf_attach

Status: auto-closed as invalid on 2022/02/20 17:36
Reported-by: syzbot+e76ced7bff2166e9f15c@syzkaller.appspotmail.com
First crash: 487d, last: 484d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 KASAN: use-after-free Read in __cgroup_bpf_attach (3) 1 226d 226d 0/2 auto-obsoleted due to no activity on 2022/11/06 11:00
android-5-10 KASAN: use-after-free Read in __cgroup_bpf_attach (2) 1 333d 333d 0/2 auto-closed as invalid on 2022/07/21 22:36

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in prog_list_prog kernel/bpf/cgroup.c:174 [inline]
BUG: KASAN: use-after-free in prog_list_length kernel/bpf/cgroup.c:187 [inline]
BUG: KASAN: use-after-free in __cgroup_bpf_attach+0x5aa/0x1070 kernel/bpf/cgroup.c:467
Read of size 8 at addr ffff88810a25d398 by task syz-executor.4/1961

CPU: 0 PID: 1961 Comm: syz-executor.4 Tainted: G        W         5.10.77-syzkaller-01258-g76698ea35fd3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x8d/0x3d0 mm/kasan/report.c:233
 __kasan_report+0x142/0x220 mm/kasan/report.c:419
 kasan_report+0x51/0x70 mm/kasan/report.c:436
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
 prog_list_prog kernel/bpf/cgroup.c:174 [inline]
 prog_list_length kernel/bpf/cgroup.c:187 [inline]
 __cgroup_bpf_attach+0x5aa/0x1070 kernel/bpf/cgroup.c:467
 cgroup_bpf_attach+0x4a/0x70 kernel/cgroup/cgroup.c:6566
 cgroup_bpf_link_attach+0x239/0x4a0 kernel/bpf/cgroup.c:934
 link_create kernel/bpf/syscall.c:4073 [inline]
 __do_sys_bpf+0xab52/0x116d0 kernel/bpf/syscall.c:4478
 __se_sys_bpf kernel/bpf/syscall.c:4364 [inline]
 __x64_sys_bpf+0x7a/0x90 kernel/bpf/syscall.c:4364
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f92cb6beae9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f92c9435188 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f92cb7d1f60 RCX: 00007f92cb6beae9
RDX: 0000000000000010 RSI: 0000000020000040 RDI: 000000000000001c
RBP: 00007f92cb718f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff17264c1f R14: 00007f92c9435300 R15: 0000000000022000

Allocated by task 1930:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:428 [inline]
 ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:507
 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:516
 kasan_kmalloc include/linux/kasan.h:269 [inline]
 kmem_cache_alloc_trace+0x210/0x3a0 mm/slub.c:2975
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:664 [inline]
 cgroup_bpf_link_attach+0x12e/0x4a0 kernel/bpf/cgroup.c:918
 link_create kernel/bpf/syscall.c:4073 [inline]
 __do_sys_bpf+0xab52/0x116d0 kernel/bpf/syscall.c:4478
 __se_sys_bpf kernel/bpf/syscall.c:4364 [inline]
 __x64_sys_bpf+0x7a/0x90 kernel/bpf/syscall.c:4364
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 1930:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:46
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:357
 ____kasan_slab_free+0x133/0x170 mm/kasan/common.c:360
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:368
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:1596 [inline]
 slab_free_freelist_hook+0xcc/0x1a0 mm/slub.c:1622
 slab_free mm/slub.c:3204 [inline]
 kfree+0xd5/0x320 mm/slub.c:4192
 bpf_cgroup_link_dealloc+0x15/0x20 kernel/bpf/cgroup.c:849
 bpf_link_free kernel/bpf/syscall.c:2336 [inline]
 bpf_link_put+0x243/0x270 kernel/bpf/syscall.c:2358
 link_detach kernel/bpf/syscall.c:4169 [inline]
 __do_sys_bpf+0x3d23/0x116d0 kernel/bpf/syscall.c:4497
 __se_sys_bpf kernel/bpf/syscall.c:4364 [inline]
 __x64_sys_bpf+0x7a/0x90 kernel/bpf/syscall.c:4364
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88810a25d380
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 24 bytes inside of
 96-byte region [ffff88810a25d380, ffff88810a25d3e0)
The buggy address belongs to the page:
page:ffffea0004289740 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88810a25d080 pfn:0x10a25d
flags: 0x8000000000000200(slab)
raw: 8000000000000200 ffffea0004699240 0000000a0000000a ffff888100043680
raw: ffff88810a25d080 000000008020001a 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 0x112c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 383, ts 51806014972, free_ts 51796809155
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2385 [inline]
 prep_new_page mm/page_alloc.c:2391 [inline]
 get_page_from_freelist+0xa74/0xa90 mm/page_alloc.c:4063
 __alloc_pages_nodemask+0x3c8/0x820 mm/page_alloc.c:5106
 alloc_slab_page mm/slub.c:1807 [inline]
 allocate_slab+0x6b/0x350 mm/slub.c:1809
 new_slab mm/slub.c:1870 [inline]
 new_slab_objects mm/slub.c:2629 [inline]
 ___slab_alloc+0x143/0x2f0 mm/slub.c:2792
 __slab_alloc mm/slub.c:2832 [inline]
 slab_alloc_node mm/slub.c:2914 [inline]
 slab_alloc mm/slub.c:2956 [inline]
 __kmalloc+0x2af/0x3d0 mm/slub.c:4030
 kmalloc_array include/linux/slab.h:592 [inline]
 kcalloc+0x36/0x50 include/linux/slab.h:603
 ext4_find_extent+0x235/0xd20 fs/ext4/extents.c:864
 ext4_ext_map_blocks+0x242/0x4340 fs/ext4/extents.c:4060
 ext4_map_blocks+0x2fc/0x1de0 fs/ext4/inode.c:563
 ext4_getblk+0x19c/0x650 fs/ext4/inode.c:848
 ext4_bread+0x2f/0x1d0 fs/ext4/inode.c:900
 ext4_append+0x175/0x310 fs/ext4/namei.c:67
 ext4_init_new_dir+0x337/0xa10 fs/ext4/namei.c:2872
 ext4_mkdir+0x485/0xbb0 fs/ext4/namei.c:2917
 vfs_mkdir+0x435/0x610 fs/namei.c:3725
 do_mkdirat+0x1f0/0x330 fs/namei.c:3748
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1331 [inline]
 free_pcp_prepare+0x18f/0x1c0 mm/page_alloc.c:1405
 free_unref_page_prepare mm/page_alloc.c:3291 [inline]
 free_unref_page mm/page_alloc.c:3341 [inline]
 free_the_page mm/page_alloc.c:5165 [inline]
 __free_pages+0x2e3/0x4a0 mm/page_alloc.c:5173
 free_pages+0x7c/0x90 mm/page_alloc.c:5184
 tlb_batch_list_free mm/mmu_gather.c:61 [inline]
 tlb_finish_mmu+0x123/0x1f0 mm/mmu_gather.c:331
 exit_mmap+0x2e8/0x570 mm/mmap.c:3326
 __mmput+0x95/0x2c0 kernel/fork.c:1128
 mmput+0x4b/0x50 kernel/fork.c:1149
 exit_mm+0x615/0x7e0 kernel/exit.c:489
 do_exit+0x6c4/0x23a0 kernel/exit.c:800
 do_group_exit+0x16a/0x2d0 kernel/exit.c:910
 __do_sys_exit_group+0x17/0x20 kernel/exit.c:921
 __se_sys_exit_group+0x14/0x20 kernel/exit.c:919
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:919
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Memory state around the buggy address:
 ffff88810a25d280: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88810a25d300: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
>ffff88810a25d380: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                            ^
 ffff88810a25d400: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88810a25d480: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-android-5-10 2021/11/22 17:31 android12-5.10-lts 76698ea35fd3 545ab074 .config console log report info KASAN: use-after-free Read in __cgroup_bpf_attach
ci2-android-5-10 2021/11/20 09:11 android12-5.10-lts 76698ea35fd3 4eb20a4e .config console log report info KASAN: use-after-free Read in __cgroup_bpf_attach
* Struck through repros no longer work on HEAD.