6.6-stable review patch. If anyone has any objections, please let me know.
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From: Amery Hung ameryhung@gmail.com
[ Upstream commit 8f12d1137c2382c80aada8e05d7cc650cd4e403c ]
It is possible for bpf_xdp_adjust_tail() to free all fragments. The kfunc currently clears the XDP_FLAGS_HAS_FRAGS bit, but not XDP_FLAGS_FRAGS_PF_MEMALLOC. So far, this has not caused a issue when building sk_buff from xdp_buff since all readers of xdp_buff->flags use the flag only when there are fragments. Clear the XDP_FLAGS_FRAGS_PF_MEMALLOC bit as well to make the flags correct.
Signed-off-by: Amery Hung ameryhung@gmail.com Signed-off-by: Martin KaFai Lau martin.lau@kernel.org Reviewed-by: Maciej Fijalkowski maciej.fijalkowski@intel.com Link: https://patch.msgid.link/20250922233356.3356453-2-ameryhung@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/xdp.h | 5 +++++ net/core/filter.c | 1 + 2 files changed, 6 insertions(+)
diff --git a/include/net/xdp.h b/include/net/xdp.h index b39ac83618a55..3d8989096b5d2 100644 --- a/include/net/xdp.h +++ b/include/net/xdp.h @@ -113,6 +113,11 @@ static __always_inline void xdp_buff_set_frag_pfmemalloc(struct xdp_buff *xdp) xdp->flags |= XDP_FLAGS_FRAGS_PF_MEMALLOC; }
+static __always_inline void xdp_buff_clear_frag_pfmemalloc(struct xdp_buff *xdp) +{ + xdp->flags &= ~XDP_FLAGS_FRAGS_PF_MEMALLOC; +} + static __always_inline void xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq) { diff --git a/net/core/filter.c b/net/core/filter.c index c2e888ea54abb..0564ee6ac8731 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4203,6 +4203,7 @@ static int bpf_xdp_frags_shrink_tail(struct xdp_buff *xdp, int offset)
if (unlikely(!sinfo->nr_frags)) { xdp_buff_clear_frags_flag(xdp); + xdp_buff_clear_frag_pfmemalloc(xdp); xdp->data_end -= offset; }