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Message-ID: <6723b2a6.050a0220.35b515.0164.GAE@google.com>
Date: Thu, 31 Oct 2024 09:39:02 -0700
From: syzbot <syzbot+41ebd857f013384237a9@...kaller.appspotmail.com>
To: eadavis@...com, linux-kernel@...r.kernel.org,
syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [exfat?] KMSAN: kernel-infoleak in pipe_read
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: kernel-infoleak in pipe_read
=====================================================
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:30 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:328 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x2f3/0x2b30 lib/iov_iter.c:185
instrument_copy_to_user include/linux/instrumented.h:114 [inline]
copy_to_user_iter lib/iov_iter.c:24 [inline]
iterate_ubuf include/linux/iov_iter.h:30 [inline]
iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
iterate_and_advance include/linux/iov_iter.h:328 [inline]
_copy_to_iter+0x2f3/0x2b30 lib/iov_iter.c:185
copy_page_to_iter+0x419/0x880 lib/iov_iter.c:362
pipe_read+0x88c/0x21a0 fs/pipe.c:327
new_sync_read fs/read_write.c:488 [inline]
vfs_read+0xcdf/0xf50 fs/read_write.c:569
ksys_read+0x24f/0x4c0 fs/read_write.c:712
__do_sys_read fs/read_write.c:722 [inline]
__se_sys_read fs/read_write.c:720 [inline]
__x64_sys_read+0x93/0xe0 fs/read_write.c:720
x64_sys_call+0x3055/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:1
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Uninit was stored to memory at:
memcpy_to_iter lib/iov_iter.c:65 [inline]
iterate_bvec include/linux/iov_iter.h:123 [inline]
iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
iterate_and_advance include/linux/iov_iter.h:328 [inline]
_copy_to_iter+0xe5a/0x2b30 lib/iov_iter.c:185
copy_page_to_iter+0x419/0x880 lib/iov_iter.c:362
shmem_file_read_iter+0xa09/0x12b0 mm/shmem.c:3164
do_iter_readv_writev+0x88a/0xa30
vfs_iter_read+0x278/0x760 fs/read_write.c:923
lo_read_simple drivers/block/loop.c:283 [inline]
do_req_filebacked drivers/block/loop.c:516 [inline]
loop_handle_cmd drivers/block/loop.c:1910 [inline]
loop_process_work+0x20fc/0x3750 drivers/block/loop.c:1945
loop_workfn+0x48/0x60 drivers/block/loop.c:1969
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310
worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391
kthread+0x3e2/0x540 kernel/kthread.c:389
ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Uninit was stored to memory at:
memcpy_from_iter lib/iov_iter.c:73 [inline]
iterate_bvec include/linux/iov_iter.h:123 [inline]
iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
iterate_and_advance include/linux/iov_iter.h:328 [inline]
__copy_from_iter lib/iov_iter.c:249 [inline]
copy_page_from_iter_atomic+0x1284/0x3090 lib/iov_iter.c:482
copy_folio_from_iter_atomic include/linux/uio.h:201 [inline]
generic_perform_write+0x8d1/0x1080 mm/filemap.c:4066
shmem_file_write_iter+0x2ba/0x2f0 mm/shmem.c:3218
do_iter_readv_writev+0x88a/0xa30
vfs_iter_write+0x44d/0xd40 fs/read_write.c:988
lo_write_bvec drivers/block/loop.c:243 [inline]
lo_write_simple drivers/block/loop.c:264 [inline]
do_req_filebacked drivers/block/loop.c:511 [inline]
loop_handle_cmd drivers/block/loop.c:1910 [inline]
loop_process_work+0x15e6/0x3750 drivers/block/loop.c:1945
loop_workfn+0x48/0x60 drivers/block/loop.c:1969
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310
worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391
kthread+0x3e2/0x540 kernel/kthread.c:389
ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Uninit was created at:
__alloc_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4756
alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2265
alloc_pages_noprof mm/mempolicy.c:2345 [inline]
folio_alloc_noprof+0x1db/0x310 mm/mempolicy.c:2352
filemap_alloc_folio_noprof+0xa6/0x440 mm/filemap.c:1010
__filemap_get_folio+0xac4/0x1550 mm/filemap.c:1952
block_write_begin+0x6e/0x2b0 fs/buffer.c:2226
exfat_write_begin+0xfb/0x400 fs/exfat/inode.c:434
exfat_extend_valid_size fs/exfat/file.c:553 [inline]
exfat_file_write_iter+0x474/0xfb0 fs/exfat/file.c:588
do_iter_readv_writev+0x88a/0xa30
vfs_writev+0x56a/0x14f0 fs/read_write.c:1064
do_pwritev fs/read_write.c:1165 [inline]
__do_sys_pwritev2 fs/read_write.c:1224 [inline]
__se_sys_pwritev2+0x280/0x470 fs/read_write.c:1215
__x64_sys_pwritev2+0x11f/0x1a0 fs/read_write.c:1215
x64_sys_call+0x2edb/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:329
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Bytes 0-1023 of 1024 are uninitialized
Memory access of size 1024 starts at ffff888039552400
Data copied to user address 000055558b7cbba0
CPU: 0 UID: 0 PID: 6309 Comm: syz-executor Not tainted 6.12.0-rc5-syzkaller-00063-g0fc810ae3ae1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
=====================================================
Tested on:
commit: 0fc810ae x86/uaccess: Avoid barrier_nospec() in 64-bit..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1028ae87980000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d4311df74eee96f
dashboard link: https://syzkaller.appspot.com/bug?extid=41ebd857f013384237a9
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=16fd2630580000
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