[syzbot] [net?] KMSAN: uninit-value in nsim_get_ringparam

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7004a2e46d16 Merge tag 'linux_kselftest-nolibc-6.14-rc1' o..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=171a1c24580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d6a5cefe7199b4e8
dashboard link: https://syzkaller.appspot.com/bug?extid=b3bcd80232d00091e061
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=16a2a9f8580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12baf618580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d5b55fed9d79/disk-7004a2e4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/70382af6f618/vmlinux-7004a2e4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a7609fc3059d/bzImage-7004a2e4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b3bcd8...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in nsim_get_ringparam+0xa8/0xe0 drivers/net/netdevsim/ethtool.c:77
nsim_get_ringparam+0xa8/0xe0 drivers/net/netdevsim/ethtool.c:77
ethtool_set_ringparam+0x268/0x570 net/ethtool/ioctl.c:2072
__dev_ethtool net/ethtool/ioctl.c:3209 [inline]
dev_ethtool+0x126d/0x2a40 net/ethtool/ioctl.c:3398
dev_ioctl+0xb0e/0x1280 net/core/dev_ioctl.c:759
sock_do_ioctl+0x28c/0x540 net/socket.c:1208
sock_ioctl+0x721/0xd70 net/socket.c:1313
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0x246/0x440 fs/ioctl.c:892
__x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:892
x64_sys_call+0x19f0/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:17
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

Local variable kernel_ringparam created at:
ethtool_set_ringparam+0x96/0x570 net/ethtool/ioctl.c:2063
__dev_ethtool net/ethtool/ioctl.c:3209 [inline]
dev_ethtool+0x126d/0x2a40 net/ethtool/ioctl.c:3398

CPU: 0 UID: 0 PID: 5807 Comm: syz-executor164 Not tainted 6.13.0-syzkaller-04788-g7004a2e46d16 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
=====================================================


---
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[syzbot]

For archival purposes, forwarding an incoming command email to
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***

Subject: Re: [syzbot] [net?] KMSAN: uninit-value in nsim_get_ringparam
Author: ku...@kernel.org

On Thu, 23 Jan 2025 08:35:28 -0800 syzbot wrote:
> HEAD commit: 7004a2e46d16 Merge tag 'linux_kselftest-nolibc-6.14-rc1' o..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=171a1c24580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d6a5cefe7199b4e8
> dashboard link: https://syzkaller.appspot.com/bug?extid=b3bcd80232d00091e061
> 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=16a2a9f8580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12baf618580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/d5b55fed9d79/disk-7004a2e4.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/70382af6f618/vmlinux-7004a2e4.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/a7609fc3059d/bzImage-7004a2e4.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b3bcd8...@syzkaller.appspotmail.com

#syz test

diff --git a/drivers/net/netdevsim/ethtool.c b/drivers/net/netdevsim/ethtool.c
index 3b23f3d3ca2b..5c80fbee7913 100644
--- a/drivers/net/netdevsim/ethtool.c
+++ b/drivers/net/netdevsim/ethtool.c
@@ -74,7 +74,7 @@ static void nsim_get_ringparam(struct net_device *dev,
memcpy(ring, &ns->ethtool.ring, sizeof(ns->ethtool.ring));
kernel_ring->hds_thresh_max = NSIM_HDS_THRESHOLD_MAX;

- if (kernel_ring->tcp_data_split == ETHTOOL_TCP_DATA_SPLIT_UNKNOWN)
+ if (dev->cfg->hds_config == ETHTOOL_TCP_DATA_SPLIT_UNKNOWN)
kernel_ring->tcp_data_split = ETHTOOL_TCP_DATA_SPLIT_ENABLED;
}

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject: Re: [syzbot] [net?] KMSAN: uninit-value in nsim_get_ringparam
Author: ku...@kernel.org

On Thu, 23 Jan 2025 08:35:28 -0800 syzbot wrote:

> HEAD commit: 7004a2e46d16 Merge tag 'linux_kselftest-nolibc-6.14-rc1' o..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=171a1c24580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d6a5cefe7199b4e8
> dashboard link: https://syzkaller.appspot.com/bug?extid=b3bcd80232d00091e061
> 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=16a2a9f8580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12baf618580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/d5b55fed9d79/disk-7004a2e4.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/70382af6f618/vmlinux-7004a2e4.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/a7609fc3059d/bzImage-7004a2e4.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b3bcd8...@syzkaller.appspotmail.com

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+b3bcd8...@syzkaller.appspotmail.com
Tested-by: syzbot+b3bcd8...@syzkaller.appspotmail.com

Tested on:

commit: d0d106a2 Merge tag 'bpf-next-6.14' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=155c0e18580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b8fbbc769f4fde1e

dashboard link: https://syzkaller.appspot.com/bug?extid=b3bcd80232d00091e061
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=121b65df980000

Note: testing is done by a robot and is best-effort only.

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+b3bcd8...@syzkaller.appspotmail.com
Tested-by: syzbot+b3bcd8...@syzkaller.appspotmail.com

Tested on:

commit: d0d106a2 Merge tag 'bpf-next-6.14' of git://git.kernel..
git tree: upstream

console output: https://syzkaller.appspot.com/x/log.txt?x=166cdab0580000

kernel config: https://syzkaller.appspot.com/x/.config?x=b8fbbc769f4fde1e
dashboard link: https://syzkaller.appspot.com/bug?extid=b3bcd80232d00091e061
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17f0dab0580000