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Bump version to 4.18.0-553.124.2

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net: skbuff: propagate shared-frag marker through pskb_copy()

Backport of https://lore.kernel.org/all/agRfuVOeMI5pbHhY@v4bel/
adapted to the 4.18 SKBTX_SHARED_FRAG / shinfo->tx_flags API.

__pskb_copy_fclone() and skb_try_coalesce() shallow-copied frag
descriptors without propagating SKBTX_SHARED_FRAG, so destinations
referencing externally-owned pages reported skb_has_shared_frag()
as false. Set the bit on the destination whenever frag descriptors
were actually moved from the source.

Reintroduce the tarfile_release indirection so pkgrelease can
advance independently of the imported source tarball.
This commit is contained in:
Andrew Lukoshko 2026-05-13 13:37:27 +00:00 committed by Andrew Lukoshko
parent 9a1521c7e1
commit 9497fbc226
2 changed files with 77 additions and 6 deletions
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65
SOURCES/1100-net-skbuff-propagate-shared-frag-marker.patch Normal file
View File

@ -0,0 +1,65 @@
From: Andrew Lukoshko <alukoshko@almalinux.org>
Subject: [PATCH AlmaLinux 8] net: skbuff: propagate shared-frag marker through pskb_copy()
Backport of upstream patch posted at
https://lore.kernel.org/all/agRfuVOeMI5pbHhY@v4bel/
(sibling to upstream commit f4c50a4034e6 "xfrm: esp: avoid in-place
decrypt on shared skb frags").
__pskb_copy_fclone() shallow-copies the source's frag descriptors and
bumps each page's refcount via skb_frag_ref(), then defers the rest
of the shinfo metadata to skb_copy_header(). That helper only carries
over gso_{size,segs,type} and never touches skb_shinfo()->tx_flags,
so the destination skb keeps a reference to the same externally-owned
or page-cache-backed pages while reporting skb_has_shared_frag() as
false.
The mismatch is harmful in any in-place writer that uses
skb_has_shared_frag() to decide whether shared pages must be detoured
through skb_cow_data().
Set SKBTX_SHARED_FRAG on the destination whenever frag descriptors
were actually moved from the source. skb_copy() and skb_copy_expand()
share skb_copy_header() too but linearize all paged data into freshly
allocated head storage and emerge with nr_frags == 0, so
skb_has_shared_frag() returns false on its own; they need no change.
Tree adaptation:
* Upstream introduces skb_shinfo()->flags and SKBFL_SHARED_FRAG
(commit 06b4feb37e69, v5.16). AlmaLinux 8 (4.18 kernel) still
uses the original SKBTX_SHARED_FRAG bit in skb_shinfo()->tx_flags,
which is also what skb_has_shared_frag() consults here. Translate
the new field/macro back to the legacy ones.
Verified to apply with `patch -p1 -F0` (no offset, no fuzz, no rejects)
against kernel-4.18.0-553.124.1.el8_10.
Fixes: cef401de7be8 ("net: fix possible wrong checksum generation")
Reported-by: William Bowling <vakzz@zellic.io>
Reported-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: Andrew Lukoshko <alukoshko@almalinux.org>
---
net/core/skbuff.c | 3 +++
1 file changed, 3 insertions(+)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1807,6 +1807,7 @@ struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
skb_frag_ref(skb, i);
}
skb_shinfo(n)->nr_frags = i;
+ skb_shinfo(n)->tx_flags |= skb_shinfo(skb)->tx_flags & SKBTX_SHARED_FRAG;
}
if (skb_has_frag_list(skb)) {
@@ -5576,6 +5577,8 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
from_shinfo->frags,
from_shinfo->nr_frags * sizeof(skb_frag_t));
to_shinfo->nr_frags += from_shinfo->nr_frags;
+ if (from_shinfo->nr_frags)
+ to_shinfo->tx_flags |= from_shinfo->tx_flags & SKBTX_SHARED_FRAG;
if (!skb_cloned(from))
from_shinfo->nr_frags = 0;
--
2.43.0

18
SPECS/kernel.spec
View File

@ -38,10 +38,11 @@
# define buildid .local
%define specversion 4.18.0
%define pkgrelease 553.124.1.el8_10
%define pkgrelease 553.124.2.el8_10
%define tarfile_release 553.124.1.el8_10
# allow pkg_release to have configurable %%{?dist} tag
%define specrelease 553.124.1%{?dist}
%define specrelease 553.124.2%{?dist}
%define pkg_release %{specrelease}%{?buildid}
@ -435,7 +436,7 @@ BuildRequires: xmlto
BuildRequires: asciidoc
%endif
Source0: linux-%{specversion}-%{pkgrelease}.tar.xz
Source0: linux-%{specversion}-%{tarfile_release}.tar.xz
Source9: x509.genkey
@ -538,6 +539,7 @@ Patch2005: 0005-Bring-back-deprecated-pci-ids-to-qla2xxx-driver.patch
Patch2006: 0006-Bring-back-deprecated-pci-ids-to-lpfc-driver.patch
Patch2007: 0007-Bring-back-deprecated-pci-ids-to-qla4xxx-driver.patch
Patch2008: 0008-Bring-back-deprecated-pci-ids-to-be2iscsi-driver.patch
Patch1100: 1100-net-skbuff-propagate-shared-frag-marker.patch
# END OF PATCH DEFINITIONS
@ -1096,9 +1098,9 @@ ApplyOptionalPatch()
fi
}
%setup -q -n %{name}-%{specversion}-%{pkgrelease} -c
cp -v %{SOURCE9000} linux-%{specversion}-%{pkgrelease}/certs/rhel.pem
mv linux-%{specversion}-%{pkgrelease} linux-%{KVERREL}
%setup -q -n %{name}-%{specversion}-%{tarfile_release} -c
cp -v %{SOURCE9000} linux-%{specversion}-%{tarfile_release}/certs/rhel.pem
mv linux-%{specversion}-%{tarfile_release} linux-%{KVERREL}
cd linux-%{KVERREL}
@ -1115,6 +1117,7 @@ ApplyPatch 0005-Bring-back-deprecated-pci-ids-to-qla2xxx-driver.patch
ApplyPatch 0006-Bring-back-deprecated-pci-ids-to-lpfc-driver.patch
ApplyPatch 0007-Bring-back-deprecated-pci-ids-to-qla4xxx-driver.patch
ApplyPatch 0008-Bring-back-deprecated-pci-ids-to-be2iscsi-driver.patch
ApplyPatch 1100-net-skbuff-propagate-shared-frag-marker.patch
# END OF PATCH APPLICATIONS
@ -2713,6 +2716,9 @@ fi
#
#
%changelog
* Wed May 13 2026 Andrew Lukoshko <alukoshko@almalinux.org> - 4.18.0-553.124.2
- net: skbuff: propagate shared-frag marker through pskb_copy()
* Tue May 12 2026 Andrei Lukoshko <alukoshko@almalinux.org> - 4.18.0-553.124.1
- hpsa: bring back deprecated PCI ids #CFHack #CFHack2024
- mptsas: bring back deprecated PCI ids #CFHack #CFHack2024