================================================================== BUG: KASAN: use-after-free in __lock_acquire.isra.16+0x13ae/0x1820 kernel/locking/lockdep.c:3668 Read of size 8 at addr ffff8881e495d628 by task jffs2_gcd_mtd0/3848 CPU: 0 PID: 3848 Comm: jffs2_gcd_mtd0 Not tainted 5.1.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x62/0x9a lib/dump_stack.c:113 print_address_description.cold.3+0x9/0x244 mm/kasan/report.c:188 __kasan_report.cold.4+0x1b/0x35 mm/kasan/report.c:317 kasan_report+0x12/0x20 mm/kasan/common.c:614 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 __lock_acquire.isra.16+0x13ae/0x1820 kernel/locking/lockdep.c:3668 lock_acquire+0x101/0x250 kernel/locking/lockdep.c:4302 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xd0/0xd80 kernel/locking/mutex.c:1072 mutex_lock_interruptible_nested+0x16/0x20 kernel/locking/mutex.c:1109 jffs2_garbage_collect_pass+0xa7/0x1858 fs/jffs2/gc.c:134 jffs2_garbage_collect_thread+0x429/0x600 fs/jffs2/background.c:155 kthread+0x2f2/0x3b0 kernel/kthread.c:253 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:352 Allocated by task 3830: save_stack mm/kasan/common.c:71 [inline] set_track mm/kasan/common.c:79 [inline] __kasan_kmalloc.part.0+0x44/0xc0 mm/kasan/common.c:489 __kasan_kmalloc.constprop.1+0xb1/0xc0 mm/kasan/common.c:470 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503 kmem_cache_alloc_trace+0x10c/0x200 mm/slub.c:2774 kmalloc include/linux/slab.h:547 [inline] kzalloc include/linux/slab.h:742 [inline] jffs2_fill_super+0x4e/0x2e0 fs/jffs2/super.c:277 mount_mtd_aux.isra.1+0xd4/0x270 drivers/mtd/mtdsuper.c:82 mount_mtd_nr.isra.2+0x84/0xa0 drivers/mtd/mtdsuper.c:119 mount_mtd+0x2fc/0x42b drivers/mtd/mtdsuper.c:172 jffs2_mount+0x10/0x20 fs/jffs2/super.c:313 legacy_get_tree+0x103/0x1f0 fs/fs_context.c:665 vfs_get_tree+0x8b/0x250 fs/super.c:1476 do_new_mount fs/namespace.c:2790 [inline] do_mount+0x10b5/0x1b30 fs/namespace.c:3110 ksys_mount+0xb1/0xd0 fs/namespace.c:3319 __do_sys_mount fs/namespace.c:3333 [inline] __se_sys_mount fs/namespace.c:3330 [inline] __x64_sys_mount+0xb9/0x150 fs/namespace.c:3330 do_syscall_64+0x9a/0x310 arch/x86/entry/common.c:298 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 3054: save_stack mm/kasan/common.c:71 [inline] set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x145/0x210 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 slab_free_hook mm/slub.c:1420 [inline] slab_free_freelist_hook mm/slub.c:1447 [inline] slab_free mm/slub.c:2994 [inline] kfree+0xce/0x240 mm/slub.c:3949 jffs2_kill_sb+0x65/0x90 fs/jffs2/super.c:344 deactivate_locked_super+0x7c/0xd0 fs/super.c:331 deactivate_super fs/super.c:362 [inline] deactivate_super+0x13f/0x160 fs/super.c:358 cleanup_mnt+0x97/0x120 fs/namespace.c:1120 __cleanup_mnt+0xd/0x10 fs/namespace.c:1127 task_work_run+0x10e/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x11f/0x150 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:276 [inline] do_syscall_64+0x294/0x310 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8881e495d500 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 296 bytes inside of 4096-byte region [ffff8881e495d500, ffff8881e495e500) The buggy address belongs to the page: page:ffffea0007925600 count:1 mapcount:0 mapping:ffff8881f6c02600 index:0x0 compound_mapcount: 0 flags: 0x200000000010200(slab|head) raw: 0200000000010200 ffffea0007917c00 0000000200000002 ffff8881f6c02600 raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2023 [inline] prep_new_page+0x235/0x300 mm/page_alloc.c:2031 get_page_from_freelist+0xf3f/0x33d0 mm/page_alloc.c:3578 __alloc_pages_nodemask+0x2eb/0x22e0 mm/page_alloc.c:4616 alloc_pages_current+0xfd/0x290 mm/mempolicy.c:2132 alloc_pages include/linux/gfp.h:509 [inline] alloc_slab_page mm/slub.c:1488 [inline] allocate_slab mm/slub.c:1633 [inline] new_slab+0x3df/0x660 mm/slub.c:1705 new_slab_objects mm/slub.c:2459 [inline] ___slab_alloc+0x5cf/0x7e0 mm/slub.c:2610 __slab_alloc+0xd/0x20 mm/slub.c:2650 slab_alloc_node mm/slub.c:2713 [inline] slab_alloc mm/slub.c:2755 [inline] kmem_cache_alloc_trace+0x1bf/0x200 mm/slub.c:2772 kmalloc include/linux/slab.h:547 [inline] kzalloc include/linux/slab.h:742 [inline] uevent_show+0x134/0x300 drivers/base/core.c:1222 dev_attr_show+0x42/0x80 drivers/base/core.c:931 sysfs_kf_seq_show+0x200/0x3d0 fs/sysfs/file.c:60 kernfs_seq_show+0x150/0x1b0 fs/kernfs/file.c:168 seq_read+0x3f4/0x1000 fs/seq_file.c:229 kernfs_fop_read+0xcc/0x5d0 fs/kernfs/file.c:252 __vfs_read+0x61/0x110 fs/read_write.c:425 vfs_read fs/read_write.c:461 [inline] vfs_read+0xf1/0x2f0 fs/read_write.c:446 Memory state around the buggy address: ffff8881e495d500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881e495d580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881e495d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881e495d680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881e495d700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================