bcachefs (loop1): reading snapshots done bcachefs (loop1): done starting filesystem ================================================================== BUG: KASAN: slab-use-after-free in bchfs_read+0x2b48/0x3350 fs/bcachefs/fs-io-buffered.c:228 Read of size 4 at addr ffff888063790148 by task syz.1.101/6586 CPU: 0 UID: 0 PID: 6586 Comm: syz.1.101 Not tainted 6.14.0-syzkaller-12456-gacc4d5ff0b61 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0x16e/0x5b0 mm/kasan/report.c:521 kasan_report+0x143/0x180 mm/kasan/report.c:634 bchfs_read+0x2b48/0x3350 fs/bcachefs/fs-io-buffered.c:228 bch2_readahead+0xe7a/0x12d0 fs/bcachefs/fs-io-buffered.c:301 read_pages+0x193/0x590 mm/readahead.c:160 page_cache_ra_order+0xa37/0xca0 mm/readahead.c:515 filemap_get_pages+0x59f/0x1fc0 mm/filemap.c:2590 filemap_read+0x466/0x1260 mm/filemap.c:2701 bch2_read_iter+0x1179/0x14b0 fs/bcachefs/fs-io-direct.c:221 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x9a0/0xb90 fs/read_write.c:570 ksys_read+0x19d/0x2d0 fs/read_write.c:713 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f07a258d169 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f07a348d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f07a27a5fa0 RCX: 00007f07a258d169 RDX: 0000000000002020 RSI: 0000200000000800 RDI: 0000000000000004 RBP: 00007f07a348d090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 00007f07a27a5fa0 R15: 00007ffe1a0025c8 Allocated by task 6586: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_mempool_unpoison_object+0x9e/0x170 mm/kasan/common.c:547 kasan_unpoison_element mm/mempool.c:-1 [inline] remove_element+0x129/0x1a0 mm/mempool.c:150 mempool_alloc_noprof+0x552/0x5a0 mm/mempool.c:408 bio_alloc_bioset+0x26f/0x1130 block/bio.c:554 bch2_readahead+0xbaf/0x12d0 fs/bcachefs/fs-io-buffered.c:290 read_pages+0x193/0x590 mm/readahead.c:160 page_cache_ra_order+0xa37/0xca0 mm/readahead.c:515 filemap_get_pages+0x59f/0x1fc0 mm/filemap.c:2590 filemap_read+0x466/0x1260 mm/filemap.c:2701 bch2_read_iter+0x1179/0x14b0 fs/bcachefs/fs-io-direct.c:221 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x9a0/0xb90 fs/read_write.c:570 ksys_read+0x19d/0x2d0 fs/read_write.c:713 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6586: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_mempool_poison_object+0xaa/0x120 mm/kasan/common.c:522 kasan_mempool_poison_object include/linux/kasan.h:360 [inline] kasan_poison_element mm/mempool.c:118 [inline] add_element mm/mempool.c:141 [inline] mempool_free+0x1c8/0x390 mm/mempool.c:541 bch2_readpages_end_io+0x17c/0x1d0 fs/bcachefs/fs-io-buffered.c:36 bch2_rbio_done fs/bcachefs/io_read.c:430 [inline] __bch2_read_extent+0x1348/0x4400 fs/bcachefs/io_read.c:1257 bch2_read_extent fs/bcachefs/io_read.h:140 [inline] bchfs_read+0x251a/0x3350 fs/bcachefs/fs-io-buffered.c:226 bch2_readahead+0xe7a/0x12d0 fs/bcachefs/fs-io-buffered.c:301 read_pages+0x193/0x590 mm/readahead.c:160 page_cache_ra_order+0xa37/0xca0 mm/readahead.c:515 filemap_get_pages+0x59f/0x1fc0 mm/filemap.c:2590 filemap_read+0x466/0x1260 mm/filemap.c:2701 bch2_read_iter+0x1179/0x14b0 fs/bcachefs/fs-io-direct.c:221 new_sync_read fs/read_write.c:489 [inline] vfs_read+0x9a0/0xb90 fs/read_write.c:570 ksys_read+0x19d/0x2d0 fs/read_write.c:713 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888063790000 which belongs to the cache bio-488 of size 488 The buggy address is located 328 bytes inside of freed 488-byte region [ffff888063790000, ffff8880637901e8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x63790 head: order:1 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 ffff88805d2c8280 dead000000000122 0000000000000000 raw: 0000000000000000 00000000800c000c 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88805d2c8280 dead000000000122 0000000000000000 head: 0000000000000000 00000000800c000c 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea00018de401 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 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 6586, tgid 6585 (syz.1.101), ts 137498560068, free_ts 137407284741 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1717 prep_new_page mm/page_alloc.c:1725 [inline] get_page_from_freelist+0x351d/0x36b0 mm/page_alloc.c:3652 __alloc_frozen_pages_noprof+0x211/0x5b0 mm/page_alloc.c:4934 alloc_pages_mpol+0x339/0x690 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2459 [inline] allocate_slab+0x8f/0x3a0 mm/slub.c:2623 new_slab mm/slub.c:2676 [inline] ___slab_alloc+0xc3b/0x1500 mm/slub.c:3862 __slab_alloc+0x58/0xa0 mm/slub.c:3952 __slab_alloc_node mm/slub.c:4027 [inline] slab_alloc_node mm/slub.c:4188 [inline] kmem_cache_alloc_noprof+0x270/0x390 mm/slub.c:4207 mempool_init_node+0x1ee/0x4e0 mm/mempool.c:217 mempool_init_noprof+0x3a/0x50 mm/mempool.c:246 bioset_init+0x2ea/0x820 block/bio.c:1709 bch2_fs_io_read_init+0x29/0xc0 fs/bcachefs/io_read.c:1377 bch2_fs_alloc fs/bcachefs/super.c:944 [inline] bch2_fs_open+0x2f2f/0x32a0 fs/bcachefs/super.c:2182 bch2_fs_get_tree+0x77b/0x18f0 fs/bcachefs/fs.c:2172 vfs_get_tree+0x90/0x2b0 fs/super.c:1759 do_new_mount+0x2cf/0xb70 fs/namespace.c:3878 page last free pid 6611 tgid 6611 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0xddf/0x10a0 mm/page_alloc.c:2680 mm_free_pgd kernel/fork.c:793 [inline] __mmdrop+0xb9/0x490 kernel/fork.c:939 exec_mmap+0x791/0x880 fs/exec.c:1009 begin_new_exec+0x12b0/0x2100 fs/exec.c:1265 load_elf_binary+0x9a2/0x28a0 fs/binfmt_elf.c:1001 search_binary_handler fs/exec.c:1773 [inline] exec_binprm fs/exec.c:1805 [inline] bprm_execve+0x97b/0x1440 fs/exec.c:1857 do_execveat_common+0x57c/0x710 fs/exec.c:1964 do_execve fs/exec.c:2038 [inline] __do_sys_execve fs/exec.c:2114 [inline] __se_sys_execve fs/exec.c:2109 [inline] __x64_sys_execve+0x94/0xb0 fs/exec.c:2109 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888063790000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888063790080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888063790100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888063790180: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff888063790200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================