================================================================== BUG: KASAN: use-after-free in jfs_lazycommit+0x74d/0xa70 fs/jfs/jfs_txnmgr.c:2736 Read of size 4 at addr ffff888024176094 by task jfsCommit/107 CPU: 0 PID: 107 Comm: jfsCommit Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 jfs_lazycommit+0x74d/0xa70 fs/jfs/jfs_txnmgr.c:2736 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 4686: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] jfs_fill_super+0xd8/0xad0 fs/jfs/super.c:495 mount_bdev+0x287/0x3c0 fs/super.c:1443 legacy_get_tree+0xe6/0x180 fs/fs_context.c:632 vfs_get_tree+0x88/0x270 fs/super.c:1573 do_new_mount+0x24a/0xa40 fs/namespace.c:3078 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 4272: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700 generic_shutdown_super+0x130/0x340 fs/super.c:501 kill_block_super+0x7c/0xe0 fs/super.c:1470 deactivate_locked_super+0x93/0xf0 fs/super.c:332 cleanup_mnt+0x42c/0x4b0 fs/namespace.c:1191 task_work_run+0x1d0/0x260 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff888024176000 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 148 bytes inside of 256-byte region [ffff888024176000, ffff888024176100) The buggy address belongs to the physical page: page:ffffea0000905d80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24176 head:ffffea0000905d80 order:1 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea0001d1b880 dead000000000005 ffff888017441b40 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 7657685701, free_ts 0 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559 prep_new_page mm/page_alloc.c:2566 [inline] get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5657 __alloc_pages_node include/linux/gfp.h:237 [inline] alloc_slab_page+0x4f/0x160 mm/slub.c:1801 allocate_slab mm/slub.c:1944 [inline] new_slab+0x87/0x2c0 mm/slub.c:1997 ___slab_alloc+0xbc6/0x1240 mm/slub.c:3154 __slab_alloc mm/slub.c:3240 [inline] slab_alloc_node mm/slub.c:3325 [inline] __kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398 kmalloc_node_trace+0x22/0xe0 mm/slab_common.c:1039 kmalloc_node include/linux/slab.h:585 [inline] kzalloc_node include/linux/slab.h:710 [inline] blk_mq_init_tags+0x71/0x280 block/blk-mq-tag.c:580 blk_mq_alloc_rq_map block/blk-mq.c:3367 [inline] blk_mq_alloc_map_and_rqs+0xc0/0x9a0 block/blk-mq.c:3862 __blk_mq_alloc_map_and_rqs block/blk-mq.c:3884 [inline] __blk_mq_alloc_rq_maps block/blk-mq.c:4418 [inline] blk_mq_alloc_set_map_and_rqs+0x1aa/0x880 block/blk-mq.c:4449 blk_mq_alloc_tag_set+0x7c5/0xe50 block/blk-mq.c:4606 loop_add+0x2ef/0x9b0 drivers/block/loop.c:2022 loop_init+0x173/0x226 drivers/block/loop.c:2263 do_one_initcall+0x26a/0x840 init/main.c:1310 do_initcall_level+0x137/0x1e4 init/main.c:1383 page_owner free stack trace missing Memory state around the buggy address: ffff888024175f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888024176000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888024176080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888024176100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888024176180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================