* [syzbot] [io-uring?] KMSAN: uninit-value in io_nop
@ 2024-11-21 14:08 syzbot
2024-11-21 14:16 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2024-11-21 14:08 UTC (permalink / raw)
To: asml.silence, axboe, io-uring, linux-kernel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 43fb83c17ba2 Merge tag 'soc-arm-6.13' of git://git.kernel...
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=134feb78580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9f17942989df952c
dashboard link: https://syzkaller.appspot.com/bug?extid=9a8500a45c2cabdf9577
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16f767f7980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12f50ec0580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e1e82262b7ac/disk-43fb83c1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7ca6e1c46dc5/vmlinux-43fb83c1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/63aaea837532/bzImage-43fb83c1.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
=====================================================
BUG: KMSAN: uninit-value in io_nop+0x549/0x8a0 io_uring/nop.c:55
io_nop+0x549/0x8a0 io_uring/nop.c:55
io_issue_sqe+0x420/0x2130 io_uring/io_uring.c:1712
io_queue_sqe io_uring/io_uring.c:1922 [inline]
io_submit_sqe io_uring/io_uring.c:2177 [inline]
io_submit_sqes+0x11bc/0x2f80 io_uring/io_uring.c:2294
__do_sys_io_uring_enter io_uring/io_uring.c:3365 [inline]
__se_sys_io_uring_enter+0x423/0x4aa0 io_uring/io_uring.c:3300
__x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3300
x64_sys_call+0xce5/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:427
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 created at:
__alloc_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4774
alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2265
alloc_pages_noprof+0x1bf/0x1e0 mm/mempolicy.c:2345
alloc_slab_page mm/slub.c:2412 [inline]
allocate_slab+0x320/0x12e0 mm/slub.c:2578
new_slab mm/slub.c:2631 [inline]
___slab_alloc+0x12ef/0x35e0 mm/slub.c:3818
__kmem_cache_alloc_bulk mm/slub.c:4895 [inline]
kmem_cache_alloc_bulk_noprof+0x486/0x1330 mm/slub.c:4967
__io_alloc_req_refill+0x84/0x5b0 io_uring/io_uring.c:958
io_alloc_req io_uring/io_uring.h:411 [inline]
io_submit_sqes+0x9a2/0x2f80 io_uring/io_uring.c:2283
__do_sys_io_uring_enter io_uring/io_uring.c:3365 [inline]
__se_sys_io_uring_enter+0x423/0x4aa0 io_uring/io_uring.c:3300
__x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3300
x64_sys_call+0xce5/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:427
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
CPU: 0 UID: 0 PID: 5798 Comm: syz-executor426 Not tainted 6.12.0-syzkaller-03657-g43fb83c17ba2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
=====================================================
---
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [io-uring?] KMSAN: uninit-value in io_nop
2024-11-21 14:08 [syzbot] [io-uring?] KMSAN: uninit-value in io_nop syzbot
@ 2024-11-21 14:16 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2024-11-21 14:16 UTC (permalink / raw)
To: syzbot, asml.silence, io-uring, linux-kernel, syzkaller-bugs
On 11/21/24 7:08 AM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 43fb83c17ba2 Merge tag 'soc-arm-6.13' of git://git.kernel...
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=134feb78580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=9f17942989df952c
> dashboard link: https://syzkaller.appspot.com/bug?extid=9a8500a45c2cabdf9577
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16f767f7980000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12f50ec0580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/e1e82262b7ac/disk-43fb83c1.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/7ca6e1c46dc5/vmlinux-43fb83c1.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/63aaea837532/bzImage-43fb83c1.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> =====================================================
> BUG: KMSAN: uninit-value in io_nop+0x549/0x8a0 io_uring/nop.c:55
> io_nop+0x549/0x8a0 io_uring/nop.c:55
> io_issue_sqe+0x420/0x2130 io_uring/io_uring.c:1712
> io_queue_sqe io_uring/io_uring.c:1922 [inline]
> io_submit_sqe io_uring/io_uring.c:2177 [inline]
> io_submit_sqes+0x11bc/0x2f80 io_uring/io_uring.c:2294
> __do_sys_io_uring_enter io_uring/io_uring.c:3365 [inline]
> __se_sys_io_uring_enter+0x423/0x4aa0 io_uring/io_uring.c:3300
> __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3300
> x64_sys_call+0xce5/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:427
> 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 created at:
> __alloc_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4774
> alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2265
> alloc_pages_noprof+0x1bf/0x1e0 mm/mempolicy.c:2345
> alloc_slab_page mm/slub.c:2412 [inline]
> allocate_slab+0x320/0x12e0 mm/slub.c:2578
> new_slab mm/slub.c:2631 [inline]
> ___slab_alloc+0x12ef/0x35e0 mm/slub.c:3818
> __kmem_cache_alloc_bulk mm/slub.c:4895 [inline]
> kmem_cache_alloc_bulk_noprof+0x486/0x1330 mm/slub.c:4967
> __io_alloc_req_refill+0x84/0x5b0 io_uring/io_uring.c:958
> io_alloc_req io_uring/io_uring.h:411 [inline]
> io_submit_sqes+0x9a2/0x2f80 io_uring/io_uring.c:2283
> __do_sys_io_uring_enter io_uring/io_uring.c:3365 [inline]
> __se_sys_io_uring_enter+0x423/0x4aa0 io_uring/io_uring.c:3300
> __x64_sys_io_uring_enter+0x11f/0x1a0 io_uring/io_uring.c:3300
> x64_sys_call+0xce5/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:427
> 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
Yep that's a bug introduced in this merge window, the below should
fix it:
commit ee116574de8415b0673c466e6cd28ba5f70c41a2
Author: Jens Axboe <[email protected]>
Date: Thu Nov 21 07:12:17 2024 -0700
io_uring/nop: ensure nop->fd is always initialized
A previous commit added file support for nop, but it only initializes
nop->fd if IORING_NOP_FIXED_FILE is set. That check should be
IORING_NOP_FILE. Fix up the condition in nop preparation, and initialize
it to a sane value even if we're not going to be directly using it.
While in there, do the same thing for the nop->buffer field.
Reported-by: [email protected]
Fixes: a85f31052bce ("io_uring/nop: add support for testing registered files and buffers")
Signed-off-by: Jens Axboe <[email protected]>
diff --git a/io_uring/nop.c b/io_uring/nop.c
index 6d470d4251ee..5e5196df650a 100644
--- a/io_uring/nop.c
+++ b/io_uring/nop.c
@@ -35,10 +35,14 @@ int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
nop->result = READ_ONCE(sqe->len);
else
nop->result = 0;
- if (nop->flags & IORING_NOP_FIXED_FILE)
+ if (nop->flags & IORING_NOP_FILE)
nop->fd = READ_ONCE(sqe->fd);
+ else
+ nop->fd = -1;
if (nop->flags & IORING_NOP_FIXED_BUFFER)
nop->buffer = READ_ONCE(sqe->buf_index);
+ else
+ nop->buffer = -1;
return 0;
}
--
Jens Axboe
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