================================================================== BUG: KASAN: slab-use-after-free in __lock_acquire+0x10c/0x7904 kernel/locking/lockdep.c:5091 Read of size 8 at addr ffff0000dc0da290 by task jffs2_gcd_mtd0/6748 CPU: 1 UID: 0 PID: 6748 Comm: jffs2_gcd_mtd0 Not tainted 6.14.0-rc5-syzkaller-g14d05f12084d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0x198/0x550 mm/kasan/report.c:521 kasan_report+0xd8/0x138 mm/kasan/report.c:634 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381 __lock_acquire+0x10c/0x7904 kernel/locking/lockdep.c:5091 lock_acquire+0x23c/0x724 kernel/locking/lockdep.c:5851 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] jffs2_garbage_collect_thread+0x178/0x488 fs/jffs2/background.c:94 kthread+0x65c/0x7b0 kernel/kthread.c:464 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862 Allocated by task 6746: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:562 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x2cc/0x428 mm/slub.c:4325 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] jffs2_init_fs_context+0x58/0xc8 fs/jffs2/super.c:314 alloc_fs_context+0x514/0x7a4 fs/fs_context.c:318 fs_context_for_mount+0x34/0x44 fs/fs_context.c:332 do_new_mount+0x14c/0x900 fs/namespace.c:3539 path_mount+0x590/0xe04 fs/namespace.c:3887 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount fs/namespace.c:4088 [inline] __arm64_sys_mount+0x4f4/0x5d0 fs/namespace.c:4088 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 Freed by task 6633: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_free_info+0x54/0x6c mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x64/0x8c mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4609 [inline] kfree+0x180/0x478 mm/slub.c:4757 jffs2_kill_sb+0x9c/0xb0 fs/jffs2/super.c:351 deactivate_locked_super+0xc4/0x12c fs/super.c:473 deactivate_super+0xe0/0x100 fs/super.c:506 cleanup_mnt+0x34c/0x3dc fs/namespace.c:1413 __cleanup_mnt+0x20/0x30 fs/namespace.c:1420 task_work_run+0x230/0x2e0 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] do_notify_resume+0x178/0x1f4 arch/arm64/kernel/entry-common.c:151 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline] el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:745 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 The buggy address belongs to the object at ffff0000dc0da000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 656 bytes inside of freed 4096-byte region [ffff0000dc0da000, ffff0000dc0db000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11c0d8 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 05ffc00000000040 ffff0000c0002140 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 05ffc00000000040 ffff0000c0002140 dead000000000122 0000000000000000 head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 05ffc00000000003 fffffdffc3703601 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000dc0da180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000dc0da200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff0000dc0da280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000dc0da300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000dc0da380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Unable to handle kernel paging request at virtual address 0053c058e00003ee Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [0053c058e00003ee] address between user and kernel address ranges Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP Modules linked in: CPU: 1 UID: 0 PID: 6748 Comm: jffs2_gcd_mtd0 Tainted: G B 6.14.0-rc5-syzkaller-g14d05f12084d #0 Tainted: [B]=BAD_PAGE Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : mtd_get_master include/linux/mtd/mtd.h:405 [inline] pc : mtd_erase+0x98/0x5cc drivers/mtd/mtdcore.c:1377 lr : mtd_get_master include/linux/mtd/mtd.h:405 [inline] lr : mtd_erase+0xb4/0x5cc drivers/mtd/mtdcore.c:1377 sp : ffff80009f0c76c0 x29: ffff80009f0c77c0 x28: dfff800000000000 x27: ffff700013e18ee8 x26: ffff80009f0c7760 x25: dfff800000000000 x24: ffff0000dc79c740 x23: ffff0000cc786000 x22: 1fffe0001b81bd10 x21: 02a202c700001f72 x20: 02a202c700001932 x19: 02a202c700001932 x18: 1fffe000366f1886 x17: ffff80008fbbd000 x16: ffff80008b7cb0d4 x15: 0000000000000001 x14: 00000000ffff8000 x13: 00000000b93f510b x12: ffff80008549a618 x11: ffff80008f31095c x10: 0000000000ff0100 x9 : 0000000000000000 x8 : 00544058e00003ee x7 : 0000000000000000 x6 : 000000000000003f x5 : 0000000000000040 x4 : 0000000000000001 x3 : ffff80008549a6c0 x2 : 0000000000000000 x1 : 0000000000000008 x0 : 0000000000000000 Call trace: mtd_get_master include/linux/mtd/mtd.h:405 [inline] (P) mtd_erase+0x98/0x5cc drivers/mtd/mtdcore.c:1377 (P) jffs2_erase_block fs/jffs2/erase.c:63 [inline] jffs2_erase_pending_blocks+0xa94/0x1fd4 fs/jffs2/erase.c:140 jffs2_garbage_collect_pass+0x554/0x1a50 fs/jffs2/gc.c:253 jffs2_garbage_collect_thread+0x410/0x488 fs/jffs2/background.c:155 kthread+0x65c/0x7b0 kernel/kthread.c:464 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862 Code: 96c81cdc aa1703f3 91190275 d343fea8 (387c6908) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: 96c81cdc bl 0xfffffffffb207370 4: aa1703f3 mov x19, x23 8: 91190275 add x21, x19, #0x640 c: d343fea8 lsr x8, x21, #3 * 10: 387c6908 ldrb w8, [x8, x28] <-- trapping instruction