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| author | Jason Baron <jbaron@akamai.com> | 2025-09-22 15:19:57 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-10-02 13:42:51 +0200 |
| commit | 31ae2fbc9fcb938b798a8f8fb61f6c54b9e79f59 (patch) | |
| tree | 4290e1ad90ca45a26724f61e5013d40d998dc2a0 | |
| parent | 98a76bd96f382f3b571a8fdd247fc96d66dad7eb (diff) | |
| download | linux-31ae2fbc9fcb938b798a8f8fb61f6c54b9e79f59.tar.gz linux-31ae2fbc9fcb938b798a8f8fb61f6c54b9e79f59.tar.bz2 linux-31ae2fbc9fcb938b798a8f8fb61f6c54b9e79f59.zip | |
net: allow alloc_skb_with_frags() to use MAX_SKB_FRAGS
[ Upstream commit ca9f9cdc4de97d0221100b11224738416696163c ]
Currently, alloc_skb_with_frags() will only fill (MAX_SKB_FRAGS - 1)
slots. I think it should use all MAX_SKB_FRAGS slots, as callers of
alloc_skb_with_frags() will size their allocation of frags based
on MAX_SKB_FRAGS.
This issue was discovered via a test patch that sets 'order' to 0
in alloc_skb_with_frags(), which effectively tests/simulates high
fragmentation. In this case sendmsg() on unix sockets will fail every
time for large allocations. If the PAGE_SIZE is 4K, then data_len will
request 68K or 17 pages, but alloc_skb_with_frags() can only allocate
64K in this case or 16 pages.
Fixes: 09c2c90705bb ("net: allow alloc_skb_with_frags() to allocate bigger packets")
Signed-off-by: Jason Baron <jbaron@akamai.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250922191957.2855612-1-jbaron@akamai.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/core/skbuff.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 21a83e26f004..867832f8bbae 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -6330,7 +6330,7 @@ struct sk_buff *alloc_skb_with_frags(unsigned long header_len, return NULL; while (data_len) { - if (nr_frags == MAX_SKB_FRAGS - 1) + if (nr_frags == MAX_SKB_FRAGS) goto failure; while (order && PAGE_ALIGN(data_len) < (PAGE_SIZE << order)) order--; |