================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline] BUG: KASAN: slab-use-after-free in atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline] BUG: KASAN: slab-use-after-free in gfs2_qd_dealloc+0x81/0xe0 fs/gfs2/quota.c:112 Write of size 4 at addr ffff888029140b68 by task ksoftirqd/1/23 CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200 instrument_atomic_read_write include/linux/instrumented.h:112 [inline] atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline] gfs2_qd_dealloc+0x81/0xe0 fs/gfs2/quota.c:112 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:626 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1067 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 19890: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5249 kmalloc_noprof include/linux/slab.h:962 [inline] kzalloc_noprof include/linux/slab.h:1204 [inline] init_sbd fs/gfs2/ops_fstype.c:79 [inline] gfs2_fill_super+0x128/0x21d0 fs/gfs2/ops_fstype.c:1121 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3760 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3836 do_mount fs/namespace.c:4159 [inline] __do_sys_mount fs/namespace.c:4348 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4325 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 19890: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2627 [inline] slab_free mm/slub.c:6013 [inline] kfree+0x1c1/0x610 mm/slub.c:6313 free_sbd fs/gfs2/ops_fstype.c:72 [inline] gfs2_fill_super+0x150e/0x21d0 fs/gfs2/ops_fstype.c:1316 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3760 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3836 do_mount fs/namespace.c:4159 [inline] __do_sys_mount fs/namespace.c:4348 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4325 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888029140000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2920 bytes inside of freed 8192-byte region [ffff888029140000, ffff888029142000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29140 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 ffff88801b027280 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b027280 dead000000000100 dead000000000122 head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000a45001 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5829, tgid 5829 (syz-executor), ts 84555196309, free_ts 55921636140 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1883 prep_new_page mm/page_alloc.c:1891 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3956 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5244 alloc_slab_page mm/slub.c:3195 [inline] allocate_slab+0x7b/0x660 mm/slub.c:3368 new_slab mm/slub.c:3426 [inline] refill_objects+0x33a/0x3d0 mm/slub.c:7002 refill_sheaf mm/slub.c:2744 [inline] __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4488 alloc_from_pcs mm/slub.c:4591 [inline] slab_alloc_node mm/slub.c:4725 [inline] __do_kmalloc_node mm/slub.c:5128 [inline] __kmalloc_noprof+0x474/0x760 mm/slub.c:5141 kmalloc_noprof include/linux/slab.h:966 [inline] kmalloc_array_noprof include/linux/slab.h:1113 [inline] cache_create_net+0x92/0x260 net/sunrpc/cache.c:1748 rsc_cache_create_net net/sunrpc/auth_gss/svcauth_gss.c:2054 [inline] gss_svc_init_net+0x58/0x570 net/sunrpc/auth_gss/svcauth_gss.c:2082 ops_init+0x35c/0x5c0 net/core/net_namespace.c:137 setup_net+0x118/0x340 net/core/net_namespace.c:446 copy_net_ns+0x3e2/0x570 net/core/net_namespace.c:581 create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:130 unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:226 ksys_unshare+0x4f4/0x900 kernel/fork.c:3173 __do_sys_unshare kernel/fork.c:3244 [inline] __se_sys_unshare kernel/fork.c:3242 [inline] __x64_sys_unshare+0x38/0x50 kernel/fork.c:3242 page last free pid 5523 tgid 5523 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1432 [inline] __free_frozen_pages+0xbb9/0xd10 mm/page_alloc.c:2972 __slab_free+0x263/0x2b0 mm/slub.c:5442 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:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4411 [inline] slab_alloc_node mm/slub.c:4740 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4747 alloc_filename fs/namei.c:142 [inline] do_getname+0x2e/0x250 fs/namei.c:182 getname include/linux/fs.h:2512 [inline] class_filename_constructor include/linux/fs.h:2539 [inline] do_sys_openat2+0xca/0x200 fs/open.c:1365 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888029140a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888029140a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888029140b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888029140b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888029140c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================