Message-ID: <000000000000d69fc4060c7d50a2@google.com>
Date: Thu, 14 Dec 2023 11:30:26 -0800
From: syzbot <syzbot+3e719fc23ab95580e4c2@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, hughd@...gle.com, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [mm?] [hfs?] KASAN: slab-out-of-bounds Write in shmem_file_read_iter

Hello,

syzbot found the following issue on:

HEAD commit:    d46efae31672 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=16803d66e80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f62dd67b72f86455
dashboard link: https://syzkaller.appspot.com/bug?extid=3e719fc23ab95580e4c2
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1743a366e80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17d5101ee80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f1c7fab7b512/disk-d46efae3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/44ed3d86d2c1/vmlinux-d46efae3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2e0b5f52455a/Image-d46efae3.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/3e3c3babb0db/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3e719fc23ab95580e4c2@...kaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy_to_iter lib/iov_iter.c:65 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_bvec include/linux/iov_iter.h:122 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance2 include/linux/iov_iter.h:249 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance include/linux/iov_iter.h:271 [inline]
BUG: KASAN: slab-out-of-bounds in _copy_to_iter+0x7dc/0x1500 lib/iov_iter.c:186
Write of size 2048 at addr ffff0000ce31a400 by task kworker/u4:5/220

CPU: 1 PID: 220 Comm: kworker/u4:5 Not tainted 6.7.0-rc4-syzkaller-gd46efae31672 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Workqueue: loop0 loop_rootcg_workfn
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233
 show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0x174/0x514 mm/kasan/report.c:475
 kasan_report+0xd8/0x138 mm/kasan/report.c:588
 kasan_check_range+0x254/0x294 mm/kasan/generic.c:187
 __asan_memcpy+0x54/0x84 mm/kasan/shadow.c:106
 memcpy_to_iter lib/iov_iter.c:65 [inline]
 iterate_bvec include/linux/iov_iter.h:122 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:249 [inline]
 iterate_and_advance include/linux/iov_iter.h:271 [inline]
 _copy_to_iter+0x7dc/0x1500 lib/iov_iter.c:186
 copy_page_to_iter+0x200/0x2f8 lib/iov_iter.c:381
 shmem_file_read_iter+0x4a0/0x9dc mm/shmem.c:2824
 do_iter_read+0x668/0xa80 fs/read_write.c:795
 vfs_iter_read+0x88/0xac fs/read_write.c:837
 lo_read_simple drivers/block/loop.c:290 [inline]
 do_req_filebacked drivers/block/loop.c:500 [inline]
 loop_handle_cmd drivers/block/loop.c:1915 [inline]
 loop_process_work+0xe9c/0x2498 drivers/block/loop.c:1950
 loop_rootcg_workfn+0x28/0x38 drivers/block/loop.c:1981
 process_one_work+0x694/0x1204 kernel/workqueue.c:2630
 process_scheduled_works kernel/workqueue.c:2703 [inline]
 worker_thread+0x938/0xef4 kernel/workqueue.c:2784
 kthread+0x288/0x310 kernel/kthread.c:388
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:857

Allocated by task 6095:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4c/0x7c mm/kasan/common.c:52
 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:511
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:198 [inline]
 __do_kmalloc_node mm/slab_common.c:1007 [inline]
 __kmalloc+0xcc/0x1b8 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 hfsplus_read_wrapper+0x46c/0xfcc fs/hfsplus/wrapper.c:181
 hfsplus_fill_super+0x2f0/0x166c fs/hfsplus/super.c:413
 mount_bdev+0x1e8/0x2b4 fs/super.c:1650
 hfsplus_mount+0x44/0x58 fs/hfsplus/super.c:641
 legacy_get_tree+0xd4/0x16c fs/fs_context.c:662
 vfs_get_tree+0x90/0x288 fs/super.c:1771
 do_new_mount+0x25c/0x8c8 fs/namespace.c:3337
 path_mount+0x590/0xe04 fs/namespace.c:3664
 do_mount fs/namespace.c:3677 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount fs/namespace.c:3863 [inline]
 __arm64_sys_mount+0x45c/0x594 fs/namespace.c:3863
 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155
 el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595

The buggy address belongs to the object at ffff0000ce31a400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 allocated 512-byte region [ffff0000ce31a400, ffff0000ce31a600)

The buggy address belongs to the physical page:
page:00000000950b7bf3 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e318
head:00000000950b7bf3 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x5ffc00000000840(slab|head|node=0|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 05ffc00000000840 ffff0000c0001c80 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000ce31a500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000ce31a580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff0000ce31a600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff0000ce31a680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000ce31a700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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