md: recovery of RAID array md0 md: md0: recovery done. ================================================================== BUG: KASAN: use-after-free in r1buf_pool_alloc+0x184/0xbc8 drivers/md/raid1.c:180 Read of size 8 at addr ffff0000ceb25200 by task md0_resync/4508 CPU: 1 PID: 4508 Comm: md0_resync Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026 Call trace: dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 print_address_description+0x88/0x218 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:420 kasan_report+0xa8/0xfc mm/kasan/report.c:524 __asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351 r1buf_pool_alloc+0x184/0xbc8 drivers/md/raid1.c:180 mempool_init_node+0x1c4/0x470 mm/mempool.c:221 mempool_init+0x50/0x68 mm/mempool.c:250 init_resync drivers/md/raid1.c:2629 [inline] raid1_sync_request+0x22c/0x26e4 drivers/md/raid1.c:2679 md_do_sync+0x2e18/0x36ec drivers/md/md.c:9158 md_thread+0x1e0/0x3cc drivers/md/md.c:8000 kthread+0x254/0x2e0 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Allocated by task 4504: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] kmalloc_trace+0x7c/0x94 mm/slab_common.c:1031 kmalloc include/linux/slab.h:563 [inline] raid1_reshape+0x590/0x102c drivers/md/raid1.c:3289 chunk_size_store+0x1ec/0x358 drivers/md/md.c:4290 md_attr_store+0x168/0x234 drivers/md/md.c:5626 sysfs_kf_write+0x1f8/0x274 fs/sysfs/file.c:140 kernfs_fop_write_iter+0x390/0x4b4 fs/kernfs/file.c:352 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x3c8/0x7c8 fs/read_write.c:584 ksys_write+0x12c/0x228 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Freed by task 4507: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xbc/0x21c mm/slub.c:3700 kfree+0xd0/0x1a8 mm/slab_common.c:988 raid1_reshape+0xc74/0x102c drivers/md/raid1.c:3332 chunk_size_store+0x1ec/0x358 drivers/md/md.c:4290 md_attr_store+0x168/0x234 drivers/md/md.c:5626 sysfs_kf_write+0x1f8/0x274 fs/sysfs/file.c:140 kernfs_fop_write_iter+0x390/0x4b4 fs/kernfs/file.c:352 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x3c8/0x7c8 fs/read_write.c:584 ksys_write+0x12c/0x228 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 The buggy address belongs to the object at ffff0000ceb25200 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 0 bytes inside of 128-byte region [ffff0000ceb25200, ffff0000ceb25280) The buggy address belongs to the physical page: page:00000000d7cf963a refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10eb25 flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 0000000000000000 dead000000000122 ffff0000c0002300 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000ceb25100: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000ceb25180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000ceb25200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000ceb25280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000ceb25300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Unable to handle kernel paging request at virtual address dfff800000000008 KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047] Mem abort info: ESR = 0x0000000096000006 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x06: level 2 translation fault Data abort info: ISV = 0, ISS = 0x00000006 CM = 0, WnR = 0 [dfff800000000008] address between user and kernel address ranges Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 4508 Comm: md0_resync Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026 pstate: 02400005 (nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : r1buf_pool_alloc+0x69c/0xbc8 drivers/md/raid1.c:198 lr : r1buf_pool_alloc+0x688/0xbc8 drivers/md/raid1.c:197 sp : ffff800021637450 x29: ffff8000216374a0 x28: 0000000000000087 x27: fffffc000328db74 x26: 0000000000000040 x25: ffff0000d568e440 x24: ffff0000d568e448 x23: 0000000000000cc0 x22: 0000000000000078 x21: dfff800000000000 x20: 0000000000000001 x19: ffff0000d568e448 x18: 1fffe00033e7697e x17: 0000000000000000 x16: ffff800011b90080 x15: fffffc000330ed00 x14: 0000000000000001 x13: 1fffff8000651b6e x12: 0000000000000000 x11: ff0080000ea37f14 x10: 0000000000000000 x9 : ffff0000d6cf4c00 x8 : 0000000000000008 x7 : fffffc000354a4c0 x6 : fffffc00033349c0 x5 : ffff0000d568e4c8 x4 : ffff0000d568e088 x3 : ffff80000ea37f28 x2 : 0000000000000001 x1 : 0000000000000008 x0 : 0000000000000000 Call trace: r1buf_pool_alloc+0x69c/0xbc8 drivers/md/raid1.c:198 mempool_init_node+0x1c4/0x470 mm/mempool.c:221 mempool_init+0x50/0x68 mm/mempool.c:250 init_resync drivers/md/raid1.c:2629 [inline] raid1_sync_request+0x22c/0x26e4 drivers/md/raid1.c:2679 md_do_sync+0x2e18/0x36ec drivers/md/md.c:9158 md_thread+0x1e0/0x3cc drivers/md/md.c:8000 kthread+0x254/0x2e0 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Code: f9400be9 9101011a f9000329 d343ff48 (38756908) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: f9400be9 ldr x9, [sp, #16] 4: 9101011a add x26, x8, #0x40 8: f9000329 str x9, [x25] c: d343ff48 lsr x8, x26, #3 * 10: 38756908 ldrb w8, [x8, x21] <-- trapping instruction