================================================================== BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:580 [inline] BUG: KASAN: slab-use-after-free in __mutex_lock+0x144/0xe80 kernel/locking/mutex.c:746 Read of size 8 at addr ffff8880351a0130 by task jffs2_gcd_mtd0/6194 CPU: 1 UID: 0 PID: 6194 Comm: jffs2_gcd_mtd0 Not tainted 6.15.0-rc7-syzkaller-00007-g4a95bc121ccd #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+0xb4/0x290 mm/kasan/report.c:521 kasan_report+0x118/0x150 mm/kasan/report.c:634 __mutex_lock_common kernel/locking/mutex.c:580 [inline] __mutex_lock+0x144/0xe80 kernel/locking/mutex.c:746 jffs2_garbage_collect_pass+0xad/0x20e0 fs/jffs2/gc.c:134 jffs2_garbage_collect_thread+0x618/0x6c0 fs/jffs2/background.c:155 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 6193: 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] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4358 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] jffs2_init_fs_context+0x4f/0xc0 fs/jffs2/super.c:314 alloc_fs_context+0x64e/0x7d0 fs/fs_context.c:318 do_new_mount+0x10e/0xa40 fs/namespace.c:3860 do_mount fs/namespace.c:4221 [inline] __do_sys_mount fs/namespace.c:4432 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4409 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6138: 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:2380 [inline] slab_free mm/slub.c:4642 [inline] kfree+0x193/0x440 mm/slub.c:4841 deactivate_locked_super+0xbc/0x130 fs/super.c:473 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1431 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50 exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x9a/0x120 kernel/entry/common.c:218 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880351a0000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 304 bytes inside of freed 4096-byte region [ffff8880351a0000, ffff8880351a1000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x351a0 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 ffff88801a042140 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801a042140 dead000000000122 0000000000000000 head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000d46801 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 6193, tgid 6191 (syz-executor.0), ts 93606097180, free_ts 92433379797 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1d8/0x230 mm/page_alloc.c:1714 prep_new_page mm/page_alloc.c:1722 [inline] get_page_from_freelist+0x21c7/0x22a0 mm/page_alloc.c:3684 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4966 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2450 [inline] allocate_slab+0x8a/0x3b0 mm/slub.c:2618 new_slab mm/slub.c:2672 [inline] ___slab_alloc+0xbfc/0x1480 mm/slub.c:3858 __slab_alloc mm/slub.c:3948 [inline] __slab_alloc_node mm/slub.c:4023 [inline] slab_alloc_node mm/slub.c:4184 [inline] __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4353 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] jffs2_init_fs_context+0x4f/0xc0 fs/jffs2/super.c:314 alloc_fs_context+0x64e/0x7d0 fs/fs_context.c:318 do_new_mount+0x10e/0xa40 fs/namespace.c:3860 do_mount fs/namespace.c:4221 [inline] __do_sys_mount fs/namespace.c:4432 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4409 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 6157 tgid 6157 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1258 [inline] __free_frozen_pages+0xb05/0xcd0 mm/page_alloc.c:2721 __slab_free+0x326/0x400 mm/slub.c:4553 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4147 [inline] slab_alloc_node mm/slub.c:4196 [inline] __do_kmalloc_node mm/slub.c:4326 [inline] __kmalloc_noprof+0x224/0x4f0 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline] tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x213/0x4b0 security/tomoyo/file.c:822 security_inode_getattr+0x12f/0x330 security/security.c:2377 vfs_getattr fs/stat.c:256 [inline] vfs_fstat fs/stat.c:278 [inline] __do_sys_newfstat fs/stat.c:546 [inline] __se_sys_newfstat fs/stat.c:543 [inline] __x64_sys_newfstat+0xfe/0x200 fs/stat.c:543 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8880351a0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880351a0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880351a0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880351a0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880351a0200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================