diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-12-18 08:18:44 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2025-12-28 10:19:11 +0100 |
| commit | c04de0c79534ec03c3efa49b72a90a55851b2c25 (patch) | |
| tree | 979874c9a8161bf4eee469cde8203bfd6a041048 /net | |
| parent | f79f9b7ace1713e4b83888c385f5f55519dfb687 (diff) | |
net: avoid prefetching NULL pointers
Aditya Gupta reported PowerPC crashes bisected to the blamed commit.
Apparently some platforms do not allow prefetch() on arbitrary pointers.
prefetch(next);
prefetch(&next->priority); // CRASH when next == NULL
Only NULL seems to be supported, with specific handling in prefetch().
Add a conditional to avoid the two prefetches and the skb->next clearing
for the last skb in the list.
Fixes: b2e9821cff6c ("net: prefech skb->priority in __dev_xmit_skb()")
Reported-by: Aditya Gupta <adityag@linux.ibm.com>
Closes: https://lore.kernel.org/netdev/e9f4abee-b132-440f-a50e-bced0868b5a7@linux.ibm.com/T/#mddc372b64ec5a3b181acc9ee3909110c391cc18a
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Aditya Gupta <adityag@linux.ibm.com>
Link: https://patch.msgid.link/20251218081844.809008-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dev.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 9094c0fb8c68..36dc5199037e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4241,9 +4241,11 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, int count = 0; llist_for_each_entry_safe(skb, next, ll_list, ll_node) { - prefetch(next); - prefetch(&next->priority); - skb_mark_not_on_list(skb); + if (next) { + prefetch(next); + prefetch(&next->priority); + skb_mark_not_on_list(skb); + } rc = dev_qdisc_enqueue(skb, q, &to_free, txq); count++; } |