syzbot


KASAN: slab-out-of-bounds Read in __futex_pivot_hash

Status: upstream: reported C repro on 2025/06/01 19:01
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+0a5079ee014f4b907817@syzkaller.appspotmail.com
First crash: 50d, last: 19d
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] futex: sync set the hash table slot 1 (1) 2025/06/02 04:37
[syzbot] [kernel?] KASAN: slab-out-of-bounds Read in __futex_pivot_hash 2 (5) 2025/06/02 03:40
Last patch testing requests (5)
Created Duration User Patch Repo Result
2025/07/13 11:44 17m retest repro upstream OK log
2025/06/02 04:38 18m hdanton@sina.com patch upstream OK log
2025/06/02 03:20 19m eadavis@qq.com patch upstream OK log
2025/06/02 03:00 13m eadavis@qq.com patch upstream report log
2025/06/01 23:16 13m hdanton@sina.com patch upstream report log

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
BUG: KASAN: slab-out-of-bounds in _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
Read of size 1 at addr ffff88806c9bf8e0 by task syz.3.1934/12790

CPU: 1 UID: 0 PID: 12790 Comm: syz.3.1934 Not tainted 6.16.0-rc2-syzkaller-00318-g739a6c93cc75 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xd2/0x2b0 mm/kasan/report.c:521
 kasan_report+0x118/0x150 mm/kasan/report.c:634
 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:557
 kasan_check_byte include/linux/kasan.h:399 [inline]
 lock_acquire+0x8d/0x360 kernel/locking/lockdep.c:5845
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 futex_rehash_private kernel/futex/core.c:213 [inline]
 __futex_pivot_hash+0x226/0x460 kernel/futex/core.c:251
 futex_hash_allocate+0xa6b/0xba0 kernel/futex/core.c:1662
 __do_sys_prctl kernel/sys.c:2825 [inline]
 __se_sys_prctl+0x9e8/0x1940 kernel/sys.c:2474
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f59bd18e929
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f59bdf22038 EFLAGS: 00000246 ORIG_RAX: 000000000000009d
RAX: ffffffffffffffda RBX: 00007f59bd3b6080 RCX: 00007f59bd18e929
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 000000000000004e
RBP: 00007f59bd210b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f59bd3b6080 R15: 00007ffe83afd408
 </TASK>

Allocated by task 12792:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4328 [inline]
 __kvmalloc_node_noprof+0x30d/0x5f0 mm/slub.c:5015
 futex_hash_allocate+0x3f4/0xba0 kernel/futex/core.c:1601
 __do_sys_prctl kernel/sys.c:2825 [inline]
 __se_sys_prctl+0x9e8/0x1940 kernel/sys.c:2474
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88806c9bf880
 which belongs to the cache kmalloc-cg-64 of size 64
The buggy address is located 32 bytes to the right of
 allocated 64-byte region [ffff88806c9bf880, ffff88806c9bf8c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6c9bf
memcg:ffff888064655001
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801a449c80 ffffea0001ab35c0 dead000000000002
raw: 0000000000000000 0000000080200020 00000000f5000000 ffff888064655001
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 5822, tgid 5822 (syz-executor), ts 97269960202, free_ts 97269136980
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21d5/0x22b0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kvmalloc_node_noprof+0x429/0x5f0 mm/slub.c:5015
 simple_xattr_alloc+0x43/0xa0 fs/xattr.c:1238
 shmem_initxattrs+0x24d/0x4b0 mm/shmem.c:4260
 security_inode_init_security+0x29d/0x3f0 security/security.c:1852
 shmem_mknod+0x1f6/0x3e0 mm/shmem.c:3847
 shmem_mkdir+0x33/0x70 mm/shmem.c:3906
 vfs_mkdir+0x303/0x510 fs/namei.c:4375
 do_mkdirat+0x247/0x590 fs/namei.c:4408
 __do_sys_mkdirat fs/namei.c:4425 [inline]
 __se_sys_mkdirat fs/namei.c:4423 [inline]
 __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4423
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
page last free pid 5822 tgid 5822 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc65/0xe60 mm/page_alloc.c:2706
 ___free_pages_bulk mm/kasan/shadow.c:332 [inline]
 __kasan_populate_vmalloc mm/kasan/shadow.c:375 [inline]
 kasan_populate_vmalloc+0x118/0x1a0 mm/kasan/shadow.c:417
 alloc_vmap_area+0xd51/0x1490 mm/vmalloc.c:2084
 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3179
 __vmalloc_node_range_noprof+0x301/0x12f0 mm/vmalloc.c:3845
 __vmalloc_node_noprof mm/vmalloc.c:3948 [inline]
 vzalloc_noprof+0xb2/0xf0 mm/vmalloc.c:4022
 alloc_counters+0xd3/0x6d0 net/ipv4/netfilter/ip_tables.c:799
 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:837 [inline]
 get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline]
 do_ip6t_get_ctl+0xa94/0x1180 net/ipv6/netfilter/ip6_tables.c:1677
 nf_getsockopt+0x26e/0x290 net/netfilter/nf_sockopt.c:116
 ipv6_getsockopt+0x1ed/0x290 net/ipv6/ipv6_sockglue.c:1493
 do_sock_getsockopt+0x360/0x650 net/socket.c:2357
 __sys_getsockopt net/socket.c:2386 [inline]
 __do_sys_getsockopt net/socket.c:2393 [inline]
 __se_sys_getsockopt net/socket.c:2390 [inline]
 __x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2390
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88806c9bf780: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88806c9bf800: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88806c9bf880: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
                                                       ^
 ffff88806c9bf900: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88806c9bf980: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================

Crashes (125):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/22 13:26 upstream 739a6c93cc75 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/22 03:31 upstream 3f75bfff44be d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/16 20:49 upstream e04c78d86a96 d1716036 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/16 07:25 upstream 08215f5486ec 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/15 18:21 upstream 8c6bc74c7f89 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/15 08:48 upstream 8c6bc74c7f89 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/14 22:16 upstream 4774cfe3543a 5f4b362d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/14 12:57 upstream 02adc1490e6d 0e8da31f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/14 01:11 upstream 02adc1490e6d 0e8da31f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/13 16:15 upstream 27605c8c0f69 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/12 13:51 upstream 2c4a1f3fe03e 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/09 14:45 upstream 19272b37aa4f 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/17 01:17 upstream 44a5ab7a7958 d1716036 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/22 16:34 upstream 739a6c93cc75 d6cdfb8a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/22 11:14 upstream 739a6c93cc75 d6cdfb8a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/22 00:52 upstream 3f75bfff44be d6cdfb8a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/21 13:05 upstream 11313e2f7812 d6cdfb8a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/21 09:39 upstream 11313e2f7812 d6cdfb8a .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/20 15:32 upstream 75f5f23f8787 804b3919 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/20 09:31 upstream 41687a5c6f8b ed3e87f7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/19 23:07 upstream fb4d33ab452e ed3e87f7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/19 22:06 upstream fb4d33ab452e ed3e87f7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/19 14:55 upstream fb4d33ab452e ed3e87f7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/19 11:05 upstream 74b4cc9b8780 ed3e87f7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/19 00:46 upstream 74b4cc9b8780 ed3e87f7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/18 12:03 upstream 52da431bf03b ca631f70 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/18 07:58 upstream 4663747812d1 74c9d252 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/18 04:28 upstream 4663747812d1 74c9d252 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/18 00:33 upstream 4663747812d1 74c9d252 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/17 22:07 upstream 4663747812d1 74c9d252 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/17 14:43 upstream 9afe652958c3 74c9d252 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/17 09:50 upstream 9afe652958c3 74c9d252 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/16 22:40 upstream e04c78d86a96 d1716036 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/15 22:13 upstream 08215f5486ec 5f4b362d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/15 15:51 upstream 8c6bc74c7f89 5f4b362d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/15 13:46 upstream 8c6bc74c7f89 5f4b362d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/15 07:25 upstream 8c6bc74c7f89 5f4b362d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/14 20:07 upstream 4774cfe3543a 5f4b362d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/14 09:11 upstream 4774cfe3543a 0e8da31f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/14 03:02 upstream 27605c8c0f69 0e8da31f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/13 19:36 upstream 27605c8c0f69 0e8da31f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/13 11:10 upstream 27605c8c0f69 98683f8f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/13 09:53 upstream 27605c8c0f69 98683f8f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/13 08:24 upstream 27605c8c0f69 98683f8f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/13 07:08 upstream 27605c8c0f69 98683f8f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/13 03:00 upstream 27605c8c0f69 98683f8f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/13 01:31 upstream 27605c8c0f69 98683f8f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/12 20:44 upstream 2c4a1f3fe03e 98683f8f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/12 07:26 upstream 488ef3560196 98683f8f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/05/28 23:11 upstream feacb1774bd5 3d2f584d .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/16 04:30 upstream 08215f5486ec 5f4b362d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/08 20:41 linux-next 475c850a7fdd 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/29 11:40 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 9aa9b43d689e fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/23 09:43 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 9aa9b43d689e d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in __futex_pivot_hash
2025/06/21 22:13 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 9aa9b43d689e d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in __futex_pivot_hash
* Struck through repros no longer work on HEAD.