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BUG: KASAN: use-after-free in crypto_poly1305_update+0x28/0x40 arch/x86/crypto/poly1305_glue.c:230
Read of size 8 at addr ffff888049757390 by task syz-executor358/5305

CPU: 0 UID: 0 PID: 5305 Comm: syz-executor358 Not tainted 6.14.0-rc2-syzkaller-00346-gba643b6d8440 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __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:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
 crypto_poly1305_update+0x28/0x40 arch/x86/crypto/poly1305_glue.c:230
 bch2_checksum+0x5fa/0x780 fs/bcachefs/checksum.c:239
 bch2_btree_node_read_done+0x1402/0x6180 fs/bcachefs/btree_io.c:1130
 btree_node_read_work+0x6dc/0x1380 fs/bcachefs/btree_io.c:1358
 bch2_btree_node_read+0x2433/0x29f0
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1789 [inline]
 bch2_btree_root_read+0x626/0x7b0 fs/bcachefs/btree_io.c:1811
 read_btree_roots+0x3d3/0xa70 fs/bcachefs/recovery.c:581
 bch2_fs_recovery+0x260f/0x3de0 fs/bcachefs/recovery.c:928
 bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0xdb7/0x17a0 fs/bcachefs/fs.c:2203
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3560
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd8b49b71ba
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff5a4d7e78 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff5a4d7e90 RCX: 00007fd8b49b71ba
RDX: 0000400000000000 RSI: 0000400000000200 RDI: 00007fff5a4d7e90
RBP: 0000400000000000 R08: 00007fff5a4d7ed0 R09: 000000000000f634
R10: 0000000002a08414 R11: 0000000000000282 R12: 0000400000000200
R13: 00007fff5a4d7ed0 R14: 0000000000000003 R15: 0000000002a08414
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x49757
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
raw: 04fff00000000000 ffffea000125d5c8 ffffea000125d5c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff888049757280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888049757300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888049757380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff888049757400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888049757480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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