================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:82 [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+0x1bc/0x11b0 fs/gfs2/log.c:1296 Read of size 8 at addr ffff88804de700a8 by task gfs2_logd/syz:s/18968 CPU: 1 UID: 0 PID: 18968 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 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 include/linux/instrumented.h:82 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] gfs2_withdrawn fs/gfs2/util.h:187 [inline] gfs2_logd+0x1bc/0x11b0 fs/gfs2/log.c:1296 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 18947: 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:5244 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 18947: 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:2621 [inline] slab_free mm/slub.c:6025 [inline] kfree+0x1c1/0x610 mm/slub.c:6335 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 ffff88804de70000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 168 bytes inside of freed 8192-byte region [ffff88804de70000, ffff88804de72000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4de70 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 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b027280 dead000000000122 0000000000000000 head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0001379c01 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 18898, tgid 18897 (syz.6.2984), ts 1602533551027, free_ts 1602416855977 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:3189 [inline] allocate_slab+0x7b/0x660 mm/slub.c:3362 new_slab mm/slub.c:3420 [inline] refill_objects+0x33a/0x3d0 mm/slub.c:7024 refill_sheaf mm/slub.c:2738 [inline] __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4483 alloc_from_pcs mm/slub.c:4586 [inline] slab_alloc_node mm/slub.c:4720 [inline] __do_kmalloc_node mm/slub.c:5123 [inline] __kmalloc_noprof+0x474/0x760 mm/slub.c:5136 kmalloc_noprof include/linux/slab.h:966 [inline] kzalloc_noprof include/linux/slab.h:1204 [inline] ops_init+0x7b/0x5c0 net/core/net_namespace.c:127 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 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 page last free pid 18886 tgid 18885 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:5437 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:4406 [inline] slab_alloc_node mm/slub.c:4735 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4742 ext4_mb_new_blocks+0x58a/0x4650 fs/ext4/mballoc.c:6298 ext4_ext_map_blocks+0x14fe/0x5760 fs/ext4/extents.c:4438 ext4_map_create_blocks+0x11d/0x540 fs/ext4/inode.c:616 ext4_map_blocks+0x7cd/0x11d0 fs/ext4/inode.c:809 ext4_getblk+0x1ca/0x780 fs/ext4/inode.c:977 ext4_bread+0x2a/0x180 fs/ext4/inode.c:1040 ext4_quota_write+0x239/0x580 fs/ext4/super.c:7371 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x368/0x720 fs/quota/quota_tree.c:136 do_insert_tree+0x256/0x10b0 fs/quota/quota_tree.c:347 do_insert_tree+0xa14/0x10b0 fs/quota/quota_tree.c:402 Memory state around the buggy address: ffff88804de6ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88804de70000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88804de70080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804de70100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804de70180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================