From: Alexander Lobakin <alobakin@pm.me>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Alexander Lobakin <alobakin@pm.me>,
Pavel Skripkin <paskripkin@gmail.com>,
davem@davemloft.net, linmiaohe@huawei.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
syzbot+80dccaee7c6630fa9dcf@syzkaller.appspotmail.com
Subject: Re: [PATCH v3] net/core/skbuff: fix passing wrong size to __alloc_skb
Date: Sun, 28 Feb 2021 19:11:59 +0000 [thread overview]
Message-ID: <20210228191150.10421-1-alobakin@pm.me> (raw)
In-Reply-To: <20210228105552.4f810700@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
From: Jakub Kicinski <kuba@kernel.org>
Date: Sun, 28 Feb 2021 10:55:52 -0800
> On Sun, 28 Feb 2021 18:14:46 +0000 Alexander Lobakin wrote:
> > > [1] WARNING in __alloc_pages_nodemask+0x5f8/0x730 mm/page_alloc.c:5014
> > > Call Trace:
> > > __alloc_pages include/linux/gfp.h:511 [inline]
> > > __alloc_pages_node include/linux/gfp.h:524 [inline]
> > > alloc_pages_node include/linux/gfp.h:538 [inline]
> > > kmalloc_large_node+0x60/0x110 mm/slub.c:3999
> > > __kmalloc_node_track_caller+0x319/0x3f0 mm/slub.c:4496
> > > __kmalloc_reserve net/core/skbuff.c:150 [inline]
> > > __alloc_skb+0x4e4/0x5a0 net/core/skbuff.c:210
> > > __netdev_alloc_skb+0x70/0x400 net/core/skbuff.c:446
> > > netdev_alloc_skb include/linux/skbuff.h:2832 [inline]
> > > qrtr_endpoint_post+0x84/0x11b0 net/qrtr/qrtr.c:442
> > > qrtr_tun_write_iter+0x11f/0x1a0 net/qrtr/tun.c:98
> > > call_write_iter include/linux/fs.h:1901 [inline]
> > > new_sync_write+0x426/0x650 fs/read_write.c:518
> > > vfs_write+0x791/0xa30 fs/read_write.c:605
> > > ksys_write+0x12d/0x250 fs/read_write.c:658
> > > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> > > entry_SYSCALL_64_after_hwframe+0x44/0xa9
> >
> > Ah, by the way. Have you tried to seek for the root cause, why
> > a request for such insanely large (at least 4 Mib) skb happens
> > in QRTR? I don't believe it's intended to be like this.
> > Now I feel that silencing this error with early return isn't
> > really correct approach for this.
>
> Right, IIUC Eric suggested we limit the length of the allocation
> to 64KB because that's the max reasonable skb length, and QRTR tun write
> results in generating a single skb. That seems like a good approach.
+1 for explicit capping max skb length to 64K.
Al
next prev parent reply other threads:[~2021-02-28 19:13 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 19:11 [PATCH] net/core/skbuff.c: __netdev_alloc_skb fix when len is greater than KMALLOC_MAX_SIZE Pavel Skripkin
2021-02-27 11:03 ` Alexander Lobakin
2021-02-27 16:41 ` [PATCH v2] net/core/skbuff: fix passing wrong size to __alloc_skb Pavel Skripkin
2021-02-27 17:51 ` [PATCH v3] " Pavel Skripkin
2021-02-28 18:14 ` Alexander Lobakin
2021-02-28 18:55 ` Jakub Kicinski
2021-02-28 19:11 ` Alexander Lobakin [this message]
2021-02-28 19:28 ` Pavel Skripkin
2021-02-28 20:10 ` Alexander Lobakin
2021-02-28 20:27 ` Pavel Skripkin
2021-02-28 23:06 ` [PATCH v4] net/qrtr: fix __netdev_alloc_skb call Pavel Skripkin
2021-02-28 23:22 ` Pavel Skripkin
2021-02-28 23:53 ` Alexander Lobakin
2021-03-01 21:30 ` patchwork-bot+netdevbpf
2021-03-01 13:09 ` [PATCH] net/core/skbuff.c: __netdev_alloc_skb fix when len is greater than KMALLOC_MAX_SIZE Eric Dumazet
2021-03-01 13:40 ` Pavel Skripkin
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