================================================================== BUG: KASAN: slab-use-after-free in bch2_str_hash_repair_key+0x2d42/0x3fa0 fs/bcachefs/str_hash.c:335 Read of size 8 at addr ffff88805ab85d28 by task syz-executor/8436 CPU: 1 UID: 0 PID: 8436 Comm: syz-executor Not tainted 6.16.0-rc1-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: 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 bch2_str_hash_repair_key+0x2d42/0x3fa0 fs/bcachefs/str_hash.c:335 __bch2_str_hash_check_key+0xa65/0xd40 fs/bcachefs/str_hash.c:394 bch2_str_hash_check_key fs/bcachefs/str_hash.h:429 [inline] bch2_readdir+0x11cd/0x16f0 fs/bcachefs/dirent.c:685 bch2_vfs_readdir+0x4d0/0x6c0 fs/bcachefs/fs.c:1581 iterate_dir+0x5af/0x770 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:410 [inline] __se_sys_getdents64+0xe4/0x260 fs/readdir.c:396 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: 0033:0x7fef397c1293 Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 72 3e f8 ff 66 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 a8 ff ff ff f7 d8 RSP: 002b:00007ffde7d92e98 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 0000555562718600 RCX: 00007fef397c1293 RDX: 0000000000008000 RSI: 0000555562718600 RDI: 0000000000000005 RBP: 00005555627185d4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000001000 R11: 0000000000000293 R12: ffffffffffffffa8 R13: 0000000000000010 R14: 00005555627185d0 R15: 00007ffde7d95150 Allocated by task 8436: 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] __kmalloc_node_track_caller_noprof+0x271/0x4e0 mm/slub.c:4347 __do_krealloc mm/slub.c:4905 [inline] krealloc_noprof+0x124/0x340 mm/slub.c:4958 __bch2_trans_kmalloc+0x26c/0xc80 fs/bcachefs/btree_iter.c:3187 bch2_trans_kmalloc_ip fs/bcachefs/btree_iter.h:604 [inline] bch2_trans_kmalloc fs/bcachefs/btree_iter.h:616 [inline] bch2_str_hash_repair_key+0x2a65/0x3fa0 fs/bcachefs/str_hash.c:251 __bch2_str_hash_check_key+0xa65/0xd40 fs/bcachefs/str_hash.c:394 bch2_str_hash_check_key fs/bcachefs/str_hash.h:429 [inline] bch2_readdir+0x11cd/0x16f0 fs/bcachefs/dirent.c:685 bch2_vfs_readdir+0x4d0/0x6c0 fs/bcachefs/fs.c:1581 iterate_dir+0x5af/0x770 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:410 [inline] __se_sys_getdents64+0xe4/0x260 fs/readdir.c:396 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 Freed by task 8436: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x18e/0x440 mm/slub.c:4842 krealloc_noprof+0x1cd/0x340 mm/slub.c:-1 __bch2_trans_kmalloc+0x26c/0xc80 fs/bcachefs/btree_iter.c:3187 bch2_trans_kmalloc_nomemzero_ip fs/bcachefs/btree_iter.h:586 [inline] bch2_trans_kmalloc_nomemzero fs/bcachefs/btree_iter.h:621 [inline] __bch2_bkey_make_mut_noupdate fs/bcachefs/btree_update.h:285 [inline] bch2_bkey_make_mut_noupdate fs/bcachefs/btree_update.h:300 [inline] bch2_str_hash_repair_key+0x2a96/0x3fa0 fs/bcachefs/str_hash.c:267 __bch2_str_hash_check_key+0xa65/0xd40 fs/bcachefs/str_hash.c:394 bch2_str_hash_check_key fs/bcachefs/str_hash.h:429 [inline] bch2_readdir+0x11cd/0x16f0 fs/bcachefs/dirent.c:685 bch2_vfs_readdir+0x4d0/0x6c0 fs/bcachefs/fs.c:1581 iterate_dir+0x5af/0x770 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:410 [inline] __se_sys_getdents64+0xe4/0x260 fs/readdir.c:396 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 ffff88805ab85d00 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 40 bytes inside of freed 64-byte region [ffff88805ab85d00, ffff88805ab85d40) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5ab85 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801a4418c0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000080200020 00000000f5000000 0000000000000000 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 5835, tgid 5835 (syz-executor), ts 75197569800, free_ts 20601564555 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] __kmalloc_node_track_caller_noprof+0x2f8/0x4e0 mm/slub.c:4347 kmemdup_noprof+0x2b/0x70 mm/util.c:137 _Z14kmemdup_noprofPKvU25pass_dynamic_object_size0mj include/linux/fortify-string.h:765 [inline] mpls_dev_sysctl_register+0xbd/0x270 net/mpls/af_mpls.c:1390 mpls_add_dev net/mpls/af_mpls.c:1460 [inline] mpls_dev_notify+0x357/0x7a0 net/mpls/af_mpls.c:1600 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline] call_netdevice_notifiers net/core/dev.c:2282 [inline] register_netdevice+0x1608/0x1ae0 net/core/dev.c:11143 veth_newlink+0x5cc/0xa50 drivers/net/veth.c:1884 rtnl_newlink_create+0x30d/0xb00 net/core/rtnetlink.c:3823 __rtnl_newlink net/core/rtnetlink.c:3940 [inline] rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4055 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6944 page last free pid 1 tgid 1 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 mm/page_alloc.c:5071 [inline] free_contig_range+0x1bd/0x4a0 mm/page_alloc.c:6927 destroy_args+0x7e/0x5d0 mm/debug_vm_pgtable.c:1009 debug_vm_pgtable+0x412/0x450 mm/debug_vm_pgtable.c:1389 do_one_initcall+0x233/0x820 init/main.c:1273 do_initcall_level+0x137/0x1f0 init/main.c:1335 do_initcalls+0x69/0xd0 init/main.c:1351 kernel_init_freeable+0x3d9/0x570 init/main.c:1583 kernel_init+0x1d/0x1d0 init/main.c:1473 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88805ab85c00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88805ab85c80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff88805ab85d00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88805ab85d80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88805ab85e00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc 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