syzbot


KASAN: slab-use-after-free Read in xfs_buf_rele (3)

Status: moderation: reported on 2025/05/02 00:49
Subsystems: xfs
[Documentation on labels]
Reported-by: syzbot+2257b6893ca6b2f7d16a@syzkaller.appspotmail.com
First crash: 6d08h, last: 6d08h
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in xfs_buf_rele xfs 2 324d 351d 0/28 auto-obsoleted due to no activity on 2024/09/11 19:16
upstream KASAN: slab-use-after-free Read in xfs_buf_rele (2) xfs 1 155d 145d 0/28 auto-obsoleted due to no activity on 2025/03/09 11:53
linux-4.14 KASAN: use-after-free Read in xfs_buf_rele xfs C 1 792d 862d 0/1 upstream: reported C repro on 2022/12/24 01:04
linux-4.19 KASAN: use-after-free Read in xfs_buf_rele syz error 3 790d 871d 0/1 upstream: reported syz repro on 2022/12/14 21:15

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in rht_key_hashfn include/linux/rhashtable.h:159 [inline]
BUG: KASAN: slab-use-after-free in rht_head_hashfn include/linux/rhashtable.h:174 [inline]
BUG: KASAN: slab-use-after-free in __rhashtable_remove_fast_one include/linux/rhashtable.h:1007 [inline]
BUG: KASAN: slab-use-after-free in __rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
BUG: KASAN: slab-use-after-free in rhashtable_remove_fast include/linux/rhashtable.h:1122 [inline]
BUG: KASAN: slab-use-after-free in xfs_buf_rele_cached fs/xfs/xfs_buf.c:925 [inline]
BUG: KASAN: slab-use-after-free in xfs_buf_rele+0x79c/0xcfc fs/xfs/xfs_buf.c:950
Read of size 4 at addr ffff0000c73a0808 by task syz.0.103/7135

CPU: 0 UID: 0 PID: 7135 Comm: syz.0.103 Not tainted 6.15.0-rc2-syzkaller-gc72692105976 #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xa8/0x254 mm/kasan/report.c:408
 print_report+0x68/0x84 mm/kasan/report.c:521
 kasan_report+0xb0/0x110 mm/kasan/report.c:634
 __asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
 rht_key_hashfn include/linux/rhashtable.h:159 [inline]
 rht_head_hashfn include/linux/rhashtable.h:174 [inline]
 __rhashtable_remove_fast_one include/linux/rhashtable.h:1007 [inline]
 __rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
 rhashtable_remove_fast include/linux/rhashtable.h:1122 [inline]
 xfs_buf_rele_cached fs/xfs/xfs_buf.c:925 [inline]
 xfs_buf_rele+0x79c/0xcfc fs/xfs/xfs_buf.c:950
 xfs_buftarg_shrink_scan+0x1d8/0x270 fs/xfs/xfs_buf.c:1679
 do_shrink_slab+0x650/0x11b0 mm/shrinker.c:437
 shrink_slab+0xc68/0xfb8 mm/shrinker.c:664
 drop_slab_node mm/vmscan.c:436 [inline]
 drop_slab+0x120/0x248 mm/vmscan.c:454
 drop_caches_sysctl_handler+0x170/0x300 fs/drop_caches.c:68
 proc_sys_call_handler+0x460/0x7e8 fs/proc/proc_sysctl.c:601
 proc_sys_write+0x2c/0x3c fs/proc/proc_sysctl.c:627
 do_iter_readv_writev+0x460/0x6a8 fs/read_write.c:-1
 vfs_writev+0x2b4/0x81c fs/read_write.c:1055
 do_writev+0x128/0x290 fs/read_write.c:1101
 __do_sys_writev fs/read_write.c:1169 [inline]
 __se_sys_writev fs/read_write.c:1166 [inline]
 __arm64_sys_writev+0x80/0x94 fs/read_write.c:1166
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

Allocated by task 7124:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4331 [inline]
 __kvmalloc_node_noprof+0x394/0x640 mm/slub.c:5016
 bucket_table_alloc lib/rhashtable.c:186 [inline]
 rhashtable_init_noprof+0x3b4/0xa10 lib/rhashtable.c:1075
 xfs_buf_cache_init+0x28/0x38 fs/xfs/xfs_buf.c:374
 xfs_perag_alloc fs/xfs/libxfs/xfs_ag.c:238 [inline]
 xfs_initialize_perag+0x208/0x5ac fs/xfs/libxfs/xfs_ag.c:279
 xfs_mountfs+0x81c/0x1bc8 fs/xfs/xfs_mount.c:848
 xfs_fs_fill_super+0xeb4/0x1230 fs/xfs/xfs_super.c:1915
 get_tree_bdev_flags+0x360/0x414 fs/super.c:1636
 get_tree_bdev+0x2c/0x3c fs/super.c:1659
 xfs_fs_get_tree+0x28/0x38 fs/xfs/xfs_super.c:1962
 vfs_get_tree+0x90/0x28c fs/super.c:1759
 do_new_mount+0x228/0x814 fs/namespace.c:3879
 path_mount+0x5b4/0xde0 fs/namespace.c:4206
 do_mount fs/namespace.c:4219 [inline]
 __do_sys_mount fs/namespace.c:4430 [inline]
 __se_sys_mount fs/namespace.c:4407 [inline]
 __arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4407
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

Freed by task 6495:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x68/0x88 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2389 [inline]
 slab_free mm/slub.c:4646 [inline]
 kfree+0x17c/0x474 mm/slub.c:4845
 kvfree+0x30/0x40 mm/slub.c:5059
 bucket_table_free+0xec/0x1a4 lib/rhashtable.c:114
 rhashtable_free_and_destroy+0x70c/0x87c lib/rhashtable.c:1173
 rhashtable_destroy+0x28/0x38 lib/rhashtable.c:1184
 xfs_buf_cache_destroy+0x20/0x30 fs/xfs/xfs_buf.c:381
 xfs_perag_uninit+0x28/0x38 fs/xfs/libxfs/xfs_ag.c:116
 xfs_group_free+0xd0/0x210 fs/xfs/libxfs/xfs_group.c:170
 xfs_free_perag_range+0x58/0x8c fs/xfs/libxfs/xfs_ag.c:133
 xfs_unmountfs+0x29c/0x310 fs/xfs/xfs_mount.c:1217
 xfs_fs_put_super+0x6c/0x144 fs/xfs/xfs_super.c:1234
 generic_shutdown_super+0x12c/0x2b8 fs/super.c:642
 kill_block_super+0x44/0x90 fs/super.c:1710
 xfs_kill_sb+0x20/0x58 fs/xfs/xfs_super.c:2220
 deactivate_locked_super+0xc4/0x12c fs/super.c:473
 deactivate_super+0xe0/0x100 fs/super.c:506
 cleanup_mnt+0x31c/0x3ac fs/namespace.c:1435
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1442
 task_work_run+0x1dc/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 do_notify_resume+0x178/0x1f8 arch/arm64/kernel/entry-common.c:151
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xb0/0x150 arch/arm64/kernel/entry-common.c:745
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600

The buggy address belongs to the object at ffff0000c73a0800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
 freed 512-byte region [ffff0000c73a0800, ffff0000c73a0a00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1073a0
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000040 ffff0000c0001c80 fffffdffc3242800 dead000000000002
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 05ffc00000000040 ffff0000c0001c80 fffffdffc3242800 dead000000000002
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 05ffc00000000002 fffffdffc31ce801 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000c73a0700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000c73a0780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff0000c73a0800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff0000c73a0880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000c73a0900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in lib/rhashtable.c:1192:34
shift exponent 4294901760 is too large for 32-bit type 'int'
CPU: 0 UID: 0 PID: 7135 Comm: syz.0.103 Tainted: G    B               6.15.0-rc2-syzkaller-gc72692105976 #0 PREEMPT 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 ubsan_epilogue+0x14/0x48 lib/ubsan.c:231
 __ubsan_handle_shift_out_of_bounds+0x2b0/0x34c lib/ubsan.c:492
 __rht_bucket_nested+0x460/0x594 lib/rhashtable.c:1192
 rht_bucket_var include/linux/rhashtable.h:296 [inline]
 __rhashtable_remove_fast_one include/linux/rhashtable.h:1008 [inline]
 __rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
 rhashtable_remove_fast include/linux/rhashtable.h:1122 [inline]
 xfs_buf_rele_cached fs/xfs/xfs_buf.c:925 [inline]
 xfs_buf_rele+0x690/0xcfc fs/xfs/xfs_buf.c:950
 xfs_buftarg_shrink_scan+0x1d8/0x270 fs/xfs/xfs_buf.c:1679
 do_shrink_slab+0x650/0x11b0 mm/shrinker.c:437
 shrink_slab+0xc68/0xfb8 mm/shrinker.c:664
 drop_slab_node mm/vmscan.c:436 [inline]
 drop_slab+0x120/0x248 mm/vmscan.c:454
 drop_caches_sysctl_handler+0x170/0x300 fs/drop_caches.c:68
 proc_sys_call_handler+0x460/0x7e8 fs/proc/proc_sysctl.c:601
 proc_sys_write+0x2c/0x3c fs/proc/proc_sysctl.c:627
 do_iter_readv_writev+0x460/0x6a8 fs/read_write.c:-1
 vfs_writev+0x2b4/0x81c fs/read_write.c:1055
 do_writev+0x128/0x290 fs/read_write.c:1101
 __do_sys_writev fs/read_write.c:1169 [inline]
 __se_sys_writev fs/read_write.c:1166 [inline]
 __arm64_sys_writev+0x80/0x94 fs/read_write.c:1166
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
---[ end trace ]---
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in lib/rhashtable.c:1193:32
shift exponent 4294901760 is too large for 32-bit type 'unsigned int'
CPU: 0 UID: 0 PID: 7135 Comm: syz.0.103 Tainted: G    B               6.15.0-rc2-syzkaller-gc72692105976 #0 PREEMPT 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 ubsan_epilogue+0x14/0x48 lib/ubsan.c:231
 __ubsan_handle_shift_out_of_bounds+0x2b0/0x34c lib/ubsan.c:492
 __rht_bucket_nested+0x4a8/0x594 lib/rhashtable.c:1193
 rht_bucket_var include/linux/rhashtable.h:296 [inline]
 __rhashtable_remove_fast_one include/linux/rhashtable.h:1008 [inline]
 __rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
 rhashtable_remove_fast include/linux/rhashtable.h:1122 [inline]
 xfs_buf_rele_cached fs/xfs/xfs_buf.c:925 [inline]
 xfs_buf_rele+0x690/0xcfc fs/xfs/xfs_buf.c:950
 xfs_buftarg_shrink_scan+0x1d8/0x270 fs/xfs/xfs_buf.c:1679
 do_shrink_slab+0x650/0x11b0 mm/shrinker.c:437
 shrink_slab+0xc68/0xfb8 mm/shrinker.c:664
 drop_slab_node mm/vmscan.c:436 [inline]
 drop_slab+0x120/0x248 mm/vmscan.c:454
 drop_caches_sysctl_handler+0x170/0x300 fs/drop_caches.c:68
 proc_sys_call_handler+0x460/0x7e8 fs/proc/proc_sysctl.c:601
 proc_sys_write+0x2c/0x3c fs/proc/proc_sysctl.c:627
 do_iter_readv_writev+0x460/0x6a8 fs/read_write.c:-1
 vfs_writev+0x2b4/0x81c fs/read_write.c:1055
 do_writev+0x128/0x290 fs/read_write.c:1101
 __do_sys_writev fs/read_write.c:1169 [inline]
 __se_sys_writev fs/read_write.c:1166 [inline]
 __arm64_sys_writev+0x80/0x94 fs/read_write.c:1166
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
---[ end trace ]---
Unable to handle kernel paging request at virtual address dfff800000000000
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[dfff800000000000] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1]  SMP
Modules linked in:
CPU: 0 UID: 0 PID: 7135 Comm: syz.0.103 Tainted: G    B               6.15.0-rc2-syzkaller-gc72692105976 #0 PREEMPT 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __rht_bucket_nested+0xbc/0x594 lib/rhashtable.c:1198
lr : nested_table_top lib/rhashtable.c:72 [inline]
lr : __rht_bucket_nested+0xb0/0x594 lib/rhashtable.c:1197
sp : ffff8000a3057300
x29: ffff8000a3057310 x28: 0000000000000002 x27: 00000000cd5ab5a0
x26: dfff800000000000 x25: 0000000000000000 x24: 00000000cd5ab5a0
x23: ffff0000c73a0880 x22: 000000004502b191 x21: 00000000ffff0000
x20: ffff0000c73a0800 x19: ffff0000c73a0804 x18: 0000000000000000
x17: 0000000000000000 x16: ffff80008ad04488 x15: ffff70001254ac48
x14: 1ffff0001254ac48 x13: 0000000000000004 x12: ffffffffffffffff
x11: ffff70001254ac48 x10: 0000000000ff0100 x9 : ffff800096f8e6e0
x8 : 0000000000000000 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000a3056bd8 x4 : ffff80008f3d4f00 x3 : ffff800082fb7028
x2 : 0000000000000000 x1 : 0000000000000008 x0 : 0000000000000000
Call trace:
 __rht_bucket_nested+0xbc/0x594 lib/rhashtable.c:1198 (P)
 rht_bucket_var include/linux/rhashtable.h:296 [inline]
 __rhashtable_remove_fast_one include/linux/rhashtable.h:1008 [inline]
 __rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
 rhashtable_remove_fast include/linux/rhashtable.h:1122 [inline]
 xfs_buf_rele_cached fs/xfs/xfs_buf.c:925 [inline]
 xfs_buf_rele+0x690/0xcfc fs/xfs/xfs_buf.c:950
 xfs_buftarg_shrink_scan+0x1d8/0x270 fs/xfs/xfs_buf.c:1679
 do_shrink_slab+0x650/0x11b0 mm/shrinker.c:437
 shrink_slab+0xc68/0xfb8 mm/shrinker.c:664
 drop_slab_node mm/vmscan.c:436 [inline]
 drop_slab+0x120/0x248 mm/vmscan.c:454
 drop_caches_sysctl_handler+0x170/0x300 fs/drop_caches.c:68
 proc_sys_call_handler+0x460/0x7e8 fs/proc/proc_sysctl.c:601
 proc_sys_write+0x2c/0x3c fs/proc/proc_sysctl.c:627
 do_iter_readv_writev+0x460/0x6a8 fs/read_write.c:-1
 vfs_writev+0x2b4/0x81c fs/read_write.c:1055
 do_writev+0x128/0x290 fs/read_write.c:1101
 __do_sys_writev fs/read_write.c:1169 [inline]
 __se_sys_writev fs/read_write.c:1166 [inline]
 __arm64_sys_writev+0x80/0x94 fs/read_write.c:1166
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Code: 9771a1f2 f94002e8 8b190d19 d343ff28 (387a6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	9771a1f2 	bl	0xfffffffffdc687c8
   4:	f94002e8 	ldr	x8, [x23]
   8:	8b190d19 	add	x25, x8, x25, lsl #3
   c:	d343ff28 	lsr	x8, x25, #3
* 10:	387a6908 	ldrb	w8, [x8, x26] <-- trapping instruction

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/28 00:40 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c72692105976 c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-use-after-free Read in xfs_buf_rele
* Struck through repros no longer work on HEAD.