The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 2ea6190f42d0416a4310e60a7fcb0b49fcbbd4fb
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122951-slurp-ascent-4d97@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 2ea6190f42d0416a4310e60a7fcb0b49fcbbd4fb Mon Sep 17 00:00:00 2001
From: Paolo Abeni <pabeni(a)redhat.com>
Date: Fri, 5 Dec 2025 19:55:16 +0100
Subject: [PATCH] mptcp: schedule rtx timer only after pushing data
The MPTCP protocol usually schedule the retransmission timer only
when there is some chances for such retransmissions to happen.
With a notable exception: __mptcp_push_pending() currently schedule
such timer unconditionally, potentially leading to unnecessary rtx
timer expiration.
The issue is present since the blamed commit below but become easily
reproducible after commit 27b0e701d387 ("mptcp: drop bogus optimization
in __mptcp_check_push()")
Fixes: 33d41c9cd74c ("mptcp: more accurate timeout")
Cc: stable(a)vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni(a)redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-3-9e4781…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e212c1374bd0..d8a7f7029164 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1623,7 +1623,7 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
struct mptcp_sendmsg_info info = {
.flags = flags,
};
- bool do_check_data_fin = false;
+ bool copied = false;
int push_count = 1;
while (mptcp_send_head(sk) && (push_count > 0)) {
@@ -1665,7 +1665,7 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
push_count--;
continue;
}
- do_check_data_fin = true;
+ copied = true;
}
}
}
@@ -1674,11 +1674,14 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
if (ssk)
mptcp_push_release(ssk, &info);
- /* ensure the rtx timer is running */
- if (!mptcp_rtx_timer_pending(sk))
- mptcp_reset_rtx_timer(sk);
- if (do_check_data_fin)
+ /* Avoid scheduling the rtx timer if no data has been pushed; the timer
+ * will be updated on positive acks by __mptcp_cleanup_una().
+ */
+ if (copied) {
+ if (!mptcp_rtx_timer_pending(sk))
+ mptcp_reset_rtx_timer(sk);
mptcp_check_send_data_fin(sk);
+ }
}
static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first)
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 2ea6190f42d0416a4310e60a7fcb0b49fcbbd4fb
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122952-supervise-regulate-a26b@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 2ea6190f42d0416a4310e60a7fcb0b49fcbbd4fb Mon Sep 17 00:00:00 2001
From: Paolo Abeni <pabeni(a)redhat.com>
Date: Fri, 5 Dec 2025 19:55:16 +0100
Subject: [PATCH] mptcp: schedule rtx timer only after pushing data
The MPTCP protocol usually schedule the retransmission timer only
when there is some chances for such retransmissions to happen.
With a notable exception: __mptcp_push_pending() currently schedule
such timer unconditionally, potentially leading to unnecessary rtx
timer expiration.
The issue is present since the blamed commit below but become easily
reproducible after commit 27b0e701d387 ("mptcp: drop bogus optimization
in __mptcp_check_push()")
Fixes: 33d41c9cd74c ("mptcp: more accurate timeout")
Cc: stable(a)vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni(a)redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-3-9e4781…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e212c1374bd0..d8a7f7029164 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1623,7 +1623,7 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
struct mptcp_sendmsg_info info = {
.flags = flags,
};
- bool do_check_data_fin = false;
+ bool copied = false;
int push_count = 1;
while (mptcp_send_head(sk) && (push_count > 0)) {
@@ -1665,7 +1665,7 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
push_count--;
continue;
}
- do_check_data_fin = true;
+ copied = true;
}
}
}
@@ -1674,11 +1674,14 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags)
if (ssk)
mptcp_push_release(ssk, &info);
- /* ensure the rtx timer is running */
- if (!mptcp_rtx_timer_pending(sk))
- mptcp_reset_rtx_timer(sk);
- if (do_check_data_fin)
+ /* Avoid scheduling the rtx timer if no data has been pushed; the timer
+ * will be updated on positive acks by __mptcp_cleanup_una().
+ */
+ if (copied) {
+ if (!mptcp_rtx_timer_pending(sk))
+ mptcp_reset_rtx_timer(sk);
mptcp_check_send_data_fin(sk);
+ }
}
static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first)
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122947-clapping-zookeeper-5d32@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Fri, 5 Dec 2025 19:55:15 +0100
Subject: [PATCH] selftests: mptcp: pm: ensure unknown flags are ignored
This validates the previous commit: the userspace can set unknown flags
-- the 7th bit is currently unused -- without errors, but only the
supported ones are printed in the endpoints dumps.
The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests,
but it validates the previous fix for an issue introduced by this commit
ID.
Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable(a)vger.kernel.org
Reviewed-by: Mat Martineau <martineau(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-2-9e4781…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/tools/testing/selftests/net/mptcp/pm_netlink.sh b/tools/testing/selftests/net/mptcp/pm_netlink.sh
index ec6a87588191..123d9d7a0278 100755
--- a/tools/testing/selftests/net/mptcp/pm_netlink.sh
+++ b/tools/testing/selftests/net/mptcp/pm_netlink.sh
@@ -192,6 +192,10 @@ check "show_endpoints" \
flush_endpoint
check "show_endpoints" "" "flush addrs"
+add_endpoint 10.0.1.1 flags unknown
+check "show_endpoints" "$(format_endpoints "1,10.0.1.1")" "ignore unknown flags"
+flush_endpoint
+
set_limits 9 1 2>/dev/null
check "get_limits" "${default_limits}" "rcv addrs above hard limit"
diff --git a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
index 65b374232ff5..99eecccbf0c8 100644
--- a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
+++ b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
@@ -24,6 +24,8 @@
#define IPPROTO_MPTCP 262
#endif
+#define MPTCP_PM_ADDR_FLAG_UNKNOWN _BITUL(7)
+
static void syntax(char *argv[])
{
fprintf(stderr, "%s add|ann|rem|csf|dsf|get|set|del|flush|dump|events|listen|accept [<args>]\n", argv[0]);
@@ -836,6 +838,8 @@ int add_addr(int fd, int pm_family, int argc, char *argv[])
flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
else if (!strcmp(tok, "fullmesh"))
flags |= MPTCP_PM_ADDR_FLAG_FULLMESH;
+ else if (!strcmp(tok, "unknown"))
+ flags |= MPTCP_PM_ADDR_FLAG_UNKNOWN;
else
error(1, errno,
"unknown flag %s", argv[arg]);
@@ -1048,6 +1052,13 @@ static void print_addr(struct rtattr *attrs, int len)
printf(",");
}
+ if (flags & MPTCP_PM_ADDR_FLAG_UNKNOWN) {
+ printf("unknown");
+ flags &= ~MPTCP_PM_ADDR_FLAG_UNKNOWN;
+ if (flags)
+ printf(",");
+ }
+
/* bump unknown flags, if any */
if (flags)
printf("0x%x", flags);
The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122947-enforced-elective-e753@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Fri, 5 Dec 2025 19:55:15 +0100
Subject: [PATCH] selftests: mptcp: pm: ensure unknown flags are ignored
This validates the previous commit: the userspace can set unknown flags
-- the 7th bit is currently unused -- without errors, but only the
supported ones are printed in the endpoints dumps.
The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests,
but it validates the previous fix for an issue introduced by this commit
ID.
Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable(a)vger.kernel.org
Reviewed-by: Mat Martineau <martineau(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-2-9e4781…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/tools/testing/selftests/net/mptcp/pm_netlink.sh b/tools/testing/selftests/net/mptcp/pm_netlink.sh
index ec6a87588191..123d9d7a0278 100755
--- a/tools/testing/selftests/net/mptcp/pm_netlink.sh
+++ b/tools/testing/selftests/net/mptcp/pm_netlink.sh
@@ -192,6 +192,10 @@ check "show_endpoints" \
flush_endpoint
check "show_endpoints" "" "flush addrs"
+add_endpoint 10.0.1.1 flags unknown
+check "show_endpoints" "$(format_endpoints "1,10.0.1.1")" "ignore unknown flags"
+flush_endpoint
+
set_limits 9 1 2>/dev/null
check "get_limits" "${default_limits}" "rcv addrs above hard limit"
diff --git a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
index 65b374232ff5..99eecccbf0c8 100644
--- a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
+++ b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
@@ -24,6 +24,8 @@
#define IPPROTO_MPTCP 262
#endif
+#define MPTCP_PM_ADDR_FLAG_UNKNOWN _BITUL(7)
+
static void syntax(char *argv[])
{
fprintf(stderr, "%s add|ann|rem|csf|dsf|get|set|del|flush|dump|events|listen|accept [<args>]\n", argv[0]);
@@ -836,6 +838,8 @@ int add_addr(int fd, int pm_family, int argc, char *argv[])
flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
else if (!strcmp(tok, "fullmesh"))
flags |= MPTCP_PM_ADDR_FLAG_FULLMESH;
+ else if (!strcmp(tok, "unknown"))
+ flags |= MPTCP_PM_ADDR_FLAG_UNKNOWN;
else
error(1, errno,
"unknown flag %s", argv[arg]);
@@ -1048,6 +1052,13 @@ static void print_addr(struct rtattr *attrs, int len)
printf(",");
}
+ if (flags & MPTCP_PM_ADDR_FLAG_UNKNOWN) {
+ printf("unknown");
+ flags &= ~MPTCP_PM_ADDR_FLAG_UNKNOWN;
+ if (flags)
+ printf(",");
+ }
+
/* bump unknown flags, if any */
if (flags)
printf("0x%x", flags);
The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122946-puppet-visiting-41e4@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Fri, 5 Dec 2025 19:55:15 +0100
Subject: [PATCH] selftests: mptcp: pm: ensure unknown flags are ignored
This validates the previous commit: the userspace can set unknown flags
-- the 7th bit is currently unused -- without errors, but only the
supported ones are printed in the endpoints dumps.
The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests,
but it validates the previous fix for an issue introduced by this commit
ID.
Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable(a)vger.kernel.org
Reviewed-by: Mat Martineau <martineau(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-2-9e4781…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/tools/testing/selftests/net/mptcp/pm_netlink.sh b/tools/testing/selftests/net/mptcp/pm_netlink.sh
index ec6a87588191..123d9d7a0278 100755
--- a/tools/testing/selftests/net/mptcp/pm_netlink.sh
+++ b/tools/testing/selftests/net/mptcp/pm_netlink.sh
@@ -192,6 +192,10 @@ check "show_endpoints" \
flush_endpoint
check "show_endpoints" "" "flush addrs"
+add_endpoint 10.0.1.1 flags unknown
+check "show_endpoints" "$(format_endpoints "1,10.0.1.1")" "ignore unknown flags"
+flush_endpoint
+
set_limits 9 1 2>/dev/null
check "get_limits" "${default_limits}" "rcv addrs above hard limit"
diff --git a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
index 65b374232ff5..99eecccbf0c8 100644
--- a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
+++ b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
@@ -24,6 +24,8 @@
#define IPPROTO_MPTCP 262
#endif
+#define MPTCP_PM_ADDR_FLAG_UNKNOWN _BITUL(7)
+
static void syntax(char *argv[])
{
fprintf(stderr, "%s add|ann|rem|csf|dsf|get|set|del|flush|dump|events|listen|accept [<args>]\n", argv[0]);
@@ -836,6 +838,8 @@ int add_addr(int fd, int pm_family, int argc, char *argv[])
flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
else if (!strcmp(tok, "fullmesh"))
flags |= MPTCP_PM_ADDR_FLAG_FULLMESH;
+ else if (!strcmp(tok, "unknown"))
+ flags |= MPTCP_PM_ADDR_FLAG_UNKNOWN;
else
error(1, errno,
"unknown flag %s", argv[arg]);
@@ -1048,6 +1052,13 @@ static void print_addr(struct rtattr *attrs, int len)
printf(",");
}
+ if (flags & MPTCP_PM_ADDR_FLAG_UNKNOWN) {
+ printf("unknown");
+ flags &= ~MPTCP_PM_ADDR_FLAG_UNKNOWN;
+ if (flags)
+ printf(",");
+ }
+
/* bump unknown flags, if any */
if (flags)
printf("0x%x", flags);
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122946-wharf-satin-c518@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Fri, 5 Dec 2025 19:55:15 +0100
Subject: [PATCH] selftests: mptcp: pm: ensure unknown flags are ignored
This validates the previous commit: the userspace can set unknown flags
-- the 7th bit is currently unused -- without errors, but only the
supported ones are printed in the endpoints dumps.
The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests,
but it validates the previous fix for an issue introduced by this commit
ID.
Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable(a)vger.kernel.org
Reviewed-by: Mat Martineau <martineau(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-2-9e4781…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/tools/testing/selftests/net/mptcp/pm_netlink.sh b/tools/testing/selftests/net/mptcp/pm_netlink.sh
index ec6a87588191..123d9d7a0278 100755
--- a/tools/testing/selftests/net/mptcp/pm_netlink.sh
+++ b/tools/testing/selftests/net/mptcp/pm_netlink.sh
@@ -192,6 +192,10 @@ check "show_endpoints" \
flush_endpoint
check "show_endpoints" "" "flush addrs"
+add_endpoint 10.0.1.1 flags unknown
+check "show_endpoints" "$(format_endpoints "1,10.0.1.1")" "ignore unknown flags"
+flush_endpoint
+
set_limits 9 1 2>/dev/null
check "get_limits" "${default_limits}" "rcv addrs above hard limit"
diff --git a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
index 65b374232ff5..99eecccbf0c8 100644
--- a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
+++ b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
@@ -24,6 +24,8 @@
#define IPPROTO_MPTCP 262
#endif
+#define MPTCP_PM_ADDR_FLAG_UNKNOWN _BITUL(7)
+
static void syntax(char *argv[])
{
fprintf(stderr, "%s add|ann|rem|csf|dsf|get|set|del|flush|dump|events|listen|accept [<args>]\n", argv[0]);
@@ -836,6 +838,8 @@ int add_addr(int fd, int pm_family, int argc, char *argv[])
flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
else if (!strcmp(tok, "fullmesh"))
flags |= MPTCP_PM_ADDR_FLAG_FULLMESH;
+ else if (!strcmp(tok, "unknown"))
+ flags |= MPTCP_PM_ADDR_FLAG_UNKNOWN;
else
error(1, errno,
"unknown flag %s", argv[arg]);
@@ -1048,6 +1052,13 @@ static void print_addr(struct rtattr *attrs, int len)
printf(",");
}
+ if (flags & MPTCP_PM_ADDR_FLAG_UNKNOWN) {
+ printf("unknown");
+ flags &= ~MPTCP_PM_ADDR_FLAG_UNKNOWN;
+ if (flags)
+ printf(",");
+ }
+
/* bump unknown flags, if any */
if (flags)
printf("0x%x", flags);
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122945-litigator-machinist-2f66@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Fri, 5 Dec 2025 19:55:15 +0100
Subject: [PATCH] selftests: mptcp: pm: ensure unknown flags are ignored
This validates the previous commit: the userspace can set unknown flags
-- the 7th bit is currently unused -- without errors, but only the
supported ones are printed in the endpoints dumps.
The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests,
but it validates the previous fix for an issue introduced by this commit
ID.
Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable(a)vger.kernel.org
Reviewed-by: Mat Martineau <martineau(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-2-9e4781…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/tools/testing/selftests/net/mptcp/pm_netlink.sh b/tools/testing/selftests/net/mptcp/pm_netlink.sh
index ec6a87588191..123d9d7a0278 100755
--- a/tools/testing/selftests/net/mptcp/pm_netlink.sh
+++ b/tools/testing/selftests/net/mptcp/pm_netlink.sh
@@ -192,6 +192,10 @@ check "show_endpoints" \
flush_endpoint
check "show_endpoints" "" "flush addrs"
+add_endpoint 10.0.1.1 flags unknown
+check "show_endpoints" "$(format_endpoints "1,10.0.1.1")" "ignore unknown flags"
+flush_endpoint
+
set_limits 9 1 2>/dev/null
check "get_limits" "${default_limits}" "rcv addrs above hard limit"
diff --git a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
index 65b374232ff5..99eecccbf0c8 100644
--- a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
+++ b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
@@ -24,6 +24,8 @@
#define IPPROTO_MPTCP 262
#endif
+#define MPTCP_PM_ADDR_FLAG_UNKNOWN _BITUL(7)
+
static void syntax(char *argv[])
{
fprintf(stderr, "%s add|ann|rem|csf|dsf|get|set|del|flush|dump|events|listen|accept [<args>]\n", argv[0]);
@@ -836,6 +838,8 @@ int add_addr(int fd, int pm_family, int argc, char *argv[])
flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
else if (!strcmp(tok, "fullmesh"))
flags |= MPTCP_PM_ADDR_FLAG_FULLMESH;
+ else if (!strcmp(tok, "unknown"))
+ flags |= MPTCP_PM_ADDR_FLAG_UNKNOWN;
else
error(1, errno,
"unknown flag %s", argv[arg]);
@@ -1048,6 +1052,13 @@ static void print_addr(struct rtattr *attrs, int len)
printf(",");
}
+ if (flags & MPTCP_PM_ADDR_FLAG_UNKNOWN) {
+ printf("unknown");
+ flags &= ~MPTCP_PM_ADDR_FLAG_UNKNOWN;
+ if (flags)
+ printf(",");
+ }
+
/* bump unknown flags, if any */
if (flags)
printf("0x%x", flags);
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 8a0e4bdddd1c998b894d879a1d22f1e745606215
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025122926-sizably-bountiful-a98b@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8a0e4bdddd1c998b894d879a1d22f1e745606215 Mon Sep 17 00:00:00 2001
From: Wei Yang <richard.weiyang(a)gmail.com>
Date: Thu, 6 Nov 2025 03:41:55 +0000
Subject: [PATCH] mm/huge_memory: merge uniform_split_supported() and
non_uniform_split_supported()
uniform_split_supported() and non_uniform_split_supported() share
significantly similar logic.
The only functional difference is that uniform_split_supported() includes
an additional check on the requested @new_order.
The reason for this check comes from the following two aspects:
* some file system or swap cache just supports order-0 folio
* the behavioral difference between uniform/non-uniform split
The behavioral difference between uniform split and non-uniform:
* uniform split splits folio directly to @new_order
* non-uniform split creates after-split folios with orders from
folio_order(folio) - 1 to new_order.
This means for non-uniform split or !new_order split we should check the
file system and swap cache respectively.
This commit unifies the logic and merge the two functions into a single
combined helper, removing redundant code and simplifying the split
support checking mechanism.
Link: https://lkml.kernel.org/r/20251106034155.21398-3-richard.weiyang@gmail.com
Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages")
Signed-off-by: Wei Yang <richard.weiyang(a)gmail.com>
Reviewed-by: Zi Yan <ziy(a)nvidia.com>
Cc: Zi Yan <ziy(a)nvidia.com>
Cc: "David Hildenbrand (Red Hat)" <david(a)kernel.org>
Cc: Baolin Wang <baolin.wang(a)linux.alibaba.com>
Cc: Barry Song <baohua(a)kernel.org>
Cc: Dev Jain <dev.jain(a)arm.com>
Cc: Lance Yang <lance.yang(a)linux.dev>
Cc: Liam Howlett <liam.howlett(a)oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com>
Cc: Nico Pache <npache(a)redhat.com>
Cc: Ryan Roberts <ryan.roberts(a)arm.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index b74708dc5b5f..19d4a5f52ca2 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -374,10 +374,8 @@ int __split_huge_page_to_list_to_order(struct page *page, struct list_head *list
unsigned int new_order, bool unmapped);
int min_order_for_split(struct folio *folio);
int split_folio_to_list(struct folio *folio, struct list_head *list);
-bool uniform_split_supported(struct folio *folio, unsigned int new_order,
- bool warns);
-bool non_uniform_split_supported(struct folio *folio, unsigned int new_order,
- bool warns);
+bool folio_split_supported(struct folio *folio, unsigned int new_order,
+ enum split_type split_type, bool warns);
int folio_split(struct folio *folio, unsigned int new_order, struct page *page,
struct list_head *list);
@@ -408,7 +406,7 @@ static inline int split_huge_page_to_order(struct page *page, unsigned int new_o
static inline int try_folio_split_to_order(struct folio *folio,
struct page *page, unsigned int new_order)
{
- if (!non_uniform_split_supported(folio, new_order, /* warns= */ false))
+ if (!folio_split_supported(folio, new_order, SPLIT_TYPE_NON_UNIFORM, /* warns= */ false))
return split_huge_page_to_order(&folio->page, new_order);
return folio_split(folio, new_order, page, NULL);
}
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4118f330c55e..d79a4bb363de 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3593,8 +3593,8 @@ static int __split_unmapped_folio(struct folio *folio, int new_order,
return 0;
}
-bool non_uniform_split_supported(struct folio *folio, unsigned int new_order,
- bool warns)
+bool folio_split_supported(struct folio *folio, unsigned int new_order,
+ enum split_type split_type, bool warns)
{
if (folio_test_anon(folio)) {
/* order-1 is not supported for anonymous THP. */
@@ -3602,48 +3602,41 @@ bool non_uniform_split_supported(struct folio *folio, unsigned int new_order,
"Cannot split to order-1 folio");
if (new_order == 1)
return false;
- } else if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) &&
- !mapping_large_folio_support(folio->mapping)) {
- /*
- * No split if the file system does not support large folio.
- * Note that we might still have THPs in such mappings due to
- * CONFIG_READ_ONLY_THP_FOR_FS. But in that case, the mapping
- * does not actually support large folios properly.
- */
- VM_WARN_ONCE(warns,
- "Cannot split file folio to non-0 order");
- return false;
- }
-
- /* Only swapping a whole PMD-mapped folio is supported */
- if (folio_test_swapcache(folio)) {
- VM_WARN_ONCE(warns,
- "Cannot split swapcache folio to non-0 order");
- return false;
- }
-
- return true;
-}
-
-/* See comments in non_uniform_split_supported() */
-bool uniform_split_supported(struct folio *folio, unsigned int new_order,
- bool warns)
-{
- if (folio_test_anon(folio)) {
- VM_WARN_ONCE(warns && new_order == 1,
- "Cannot split to order-1 folio");
- if (new_order == 1)
- return false;
- } else if (new_order) {
+ } else if (split_type == SPLIT_TYPE_NON_UNIFORM || new_order) {
if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) &&
!mapping_large_folio_support(folio->mapping)) {
+ /*
+ * We can always split a folio down to a single page
+ * (new_order == 0) uniformly.
+ *
+ * For any other scenario
+ * a) uniform split targeting a large folio
+ * (new_order > 0)
+ * b) any non-uniform split
+ * we must confirm that the file system supports large
+ * folios.
+ *
+ * Note that we might still have THPs in such
+ * mappings, which is created from khugepaged when
+ * CONFIG_READ_ONLY_THP_FOR_FS is enabled. But in that
+ * case, the mapping does not actually support large
+ * folios properly.
+ */
VM_WARN_ONCE(warns,
"Cannot split file folio to non-0 order");
return false;
}
}
- if (new_order && folio_test_swapcache(folio)) {
+ /*
+ * swapcache folio could only be split to order 0
+ *
+ * non-uniform split creates after-split folios with orders from
+ * folio_order(folio) - 1 to new_order, making it not suitable for any
+ * swapcache folio split. Only uniform split to order-0 can be used
+ * here.
+ */
+ if ((split_type == SPLIT_TYPE_NON_UNIFORM || new_order) && folio_test_swapcache(folio)) {
VM_WARN_ONCE(warns,
"Cannot split swapcache folio to non-0 order");
return false;
@@ -3711,11 +3704,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
if (new_order >= old_order)
return -EINVAL;
- if (split_type == SPLIT_TYPE_UNIFORM && !uniform_split_supported(folio, new_order, true))
- return -EINVAL;
-
- if (split_type == SPLIT_TYPE_NON_UNIFORM &&
- !non_uniform_split_supported(folio, new_order, true))
+ if (!folio_split_supported(folio, new_order, split_type, /* warn = */ true))
return -EINVAL;
is_hzp = is_huge_zero_folio(folio);