================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: slab-use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] BUG: KASAN: slab-use-after-free in gfs2_withdrawn fs/gfs2/util.h:187 [inline] BUG: KASAN: slab-use-after-free in gfs2_logd+0x189/0x1080 fs/gfs2/log.c:1295 Read of size 8 at addr ffff88807ca500a8 by task gfs2_logd/syz:s/20950 CPU: 1 UID: 0 PID: 20950 Comm: gfs2_logd/syz:s Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] gfs2_withdrawn fs/gfs2/util.h:187 [inline] gfs2_logd+0x189/0x1080 fs/gfs2/log.c:1295 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Allocated by task 20937: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5776 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] init_sbd fs/gfs2/ops_fstype.c:79 [inline] gfs2_fill_super+0x11f/0x21b0 fs/gfs2/ops_fstype.c:1121 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332 vfs_get_tree+0x92/0x2a0 fs/super.c:1751 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3636 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3712 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 20937: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kfree+0x1c0/0x660 mm/slub.c:6878 free_sbd fs/gfs2/ops_fstype.c:72 [inline] gfs2_fill_super+0x14ef/0x21b0 fs/gfs2/ops_fstype.c:1316 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332 vfs_get_tree+0x92/0x2a0 fs/super.c:1751 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3636 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3712 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807ca50000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 168 bytes inside of freed 8192-byte region [ffff88807ca50000, ffff88807ca52000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7ca50 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813ffa7280 ffffea0000c80200 0000000000000002 raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813ffa7280 ffffea0000c80200 0000000000000002 head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0001f29401 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x528c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP), pid 17903, tgid 17902 (syz.4.2467), ts 1288453736968, free_ts 1288408185798 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0x24e0/0x2580 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3b0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xe53/0x1820 mm/slub.c:4656 __slab_alloc+0x65/0x100 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kvmalloc_node_noprof+0x6b6/0x920 mm/slub.c:7136 netlink_alloc_large_skb+0x62/0x110 net/netlink/af_netlink.c:1186 netlink_sendmsg+0x5c6/0xb30 net/netlink/af_netlink.c:1869 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 sock_sendmsg+0x158/0x230 net/socket.c:765 splice_to_socket+0x8f5/0xf00 fs/splice.c:886 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x101/0x160 fs/splice.c:1161 splice_direct_to_actor+0x5a8/0xcc0 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x181/0x270 fs/splice.c:1230 page last free pid 17903 tgid 17902 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943 discard_slab mm/slub.c:3346 [inline] __put_partials+0x146/0x170 mm/slub.c:3886 __slab_free+0x294/0x320 mm/slub.c:5952 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:349 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_noprof+0x3cf/0x800 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] copy_splice_read+0x143/0xa50 fs/splice.c:337 do_splice_read fs/splice.c:982 [inline] splice_direct_to_actor+0x4a9/0xcc0 fs/splice.c:1086 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x181/0x270 fs/splice.c:1230 do_sendfile+0x4da/0x7e0 fs/read_write.c:1370 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88807ca4ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807ca50000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807ca50080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807ca50100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807ca50180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================