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 fdf0f60a2bb02ba581d9e71d583e69dd0714a521
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025072855-ligament-reliable-75fa@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From fdf0f60a2bb02ba581d9e71d583e69dd0714a521 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe(a)kernel.org>
Date: Tue, 15 Jul 2025 20:43:29 +0200
Subject: [PATCH] selftests: mptcp: connect: also cover checksum
The checksum mode has been added a while ago, but it is only validated
when manually launching mptcp_connect.sh with "-C".
The different CIs were then not validating these MPTCP Connect tests
with checksum enabled. To make sure they do, add a new test program
executing mptcp_connect.sh with the checksum mode.
Fixes: 94d66ba1d8e4 ("selftests: mptcp: enable checksum in mptcp_connect.sh")
Cc: stable(a)vger.kernel.org
Reviewed-by: Geliang Tang <geliang(a)kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org>
Link: https://patch.msgid.link/20250715-net-mptcp-sft-connect-alt-v2-2-8230ddd824…
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
diff --git a/tools/testing/selftests/net/mptcp/Makefile b/tools/testing/selftests/net/mptcp/Makefile
index c6b030babba8..4c7e51336ab2 100644
--- a/tools/testing/selftests/net/mptcp/Makefile
+++ b/tools/testing/selftests/net/mptcp/Makefile
@@ -5,7 +5,7 @@ top_srcdir = ../../../../..
CFLAGS += -Wall -Wl,--no-as-needed -O2 -g -I$(top_srcdir)/usr/include $(KHDR_INCLUDES)
TEST_PROGS := mptcp_connect.sh mptcp_connect_mmap.sh mptcp_connect_sendfile.sh \
- pm_netlink.sh mptcp_join.sh diag.sh \
+ mptcp_connect_checksum.sh pm_netlink.sh mptcp_join.sh diag.sh \
simult_flows.sh mptcp_sockopt.sh userspace_pm.sh
TEST_GEN_FILES = mptcp_connect pm_nl_ctl mptcp_sockopt mptcp_inq mptcp_diag
diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect_checksum.sh b/tools/testing/selftests/net/mptcp/mptcp_connect_checksum.sh
new file mode 100755
index 000000000000..ce93ec2f107f
--- /dev/null
+++ b/tools/testing/selftests/net/mptcp/mptcp_connect_checksum.sh
@@ -0,0 +1,5 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+MPTCP_LIB_KSFT_TEST="$(basename "${0}" .sh)" \
+ "$(dirname "${0}")/mptcp_connect.sh" -C "${@}"
By inducing delays in the right places, Jann Horn created a reproducer
for a hard to hit UAF issue that became possible after VMAs were allowed
to be recycled by adding SLAB_TYPESAFE_BY_RCU to their cache.
Race description is borrowed from Jann's discovery report:
lock_vma_under_rcu() looks up a VMA locklessly with mas_walk() under
rcu_read_lock(). At that point, the VMA may be concurrently freed, and
it can be recycled by another process. vma_start_read() then
increments the vma->vm_refcnt (if it is in an acceptable range), and
if this succeeds, vma_start_read() can return a recycled VMA.
In this scenario where the VMA has been recycled, lock_vma_under_rcu()
will then detect the mismatching ->vm_mm pointer and drop the VMA
through vma_end_read(), which calls vma_refcount_put().
vma_refcount_put() drops the refcount and then calls rcuwait_wake_up()
using a copy of vma->vm_mm. This is wrong: It implicitly assumes that
the caller is keeping the VMA's mm alive, but in this scenario the caller
has no relation to the VMA's mm, so the rcuwait_wake_up() can cause UAF.
The diagram depicting the race:
T1 T2 T3
== == ==
lock_vma_under_rcu
mas_walk
<VMA gets removed from mm>
mmap
<the same VMA is reallocated>
vma_start_read
__refcount_inc_not_zero_limited_acquire
munmap
__vma_enter_locked
refcount_add_not_zero
vma_end_read
vma_refcount_put
__refcount_dec_and_test
rcuwait_wait_event
<finish operation>
rcuwait_wake_up [UAF]
Note that rcuwait_wait_event() in T3 does not block because refcount
was already dropped by T1. At this point T3 can exit and free the mm
causing UAF in T1.
To avoid this we move vma->vm_mm verification into vma_start_read() and
grab vma->vm_mm to stabilize it before vma_refcount_put() operation.
Fixes: 3104138517fc ("mm: make vma cache SLAB_TYPESAFE_BY_RCU")
Reported-by: Jann Horn <jannh(a)google.com>
Closes: https://lore.kernel.org/all/CAG48ez0-deFbVH=E3jbkWx=X3uVbd8nWeo6kbJPQ0KoUD+…
Signed-off-by: Suren Baghdasaryan <surenb(a)google.com>
Cc: <stable(a)vger.kernel.org>
---
Changes since v1 [1]
- Made a copy of vma->mm before using it in vma_start_read(),
per Vlastimil Babka
Notes:
- Applies cleanly over mm-unstable.
- Should be applied to 6.15 and 6.16 but these branches do not
have lock_next_vma() function, so the change in lock_next_vma() should be
skipped when applying to those branches.
[1] https://lore.kernel.org/all/20250728170950.2216966-1-surenb@google.com/
include/linux/mmap_lock.h | 23 +++++++++++++++++++++++
mm/mmap_lock.c | 10 +++-------
2 files changed, 26 insertions(+), 7 deletions(-)
diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h
index 1f4f44951abe..da34afa2f8ef 100644
--- a/include/linux/mmap_lock.h
+++ b/include/linux/mmap_lock.h
@@ -12,6 +12,7 @@ extern int rcuwait_wake_up(struct rcuwait *w);
#include <linux/tracepoint-defs.h>
#include <linux/types.h>
#include <linux/cleanup.h>
+#include <linux/sched/mm.h>
#define MMAP_LOCK_INITIALIZER(name) \
.mmap_lock = __RWSEM_INITIALIZER((name).mmap_lock),
@@ -183,6 +184,28 @@ static inline struct vm_area_struct *vma_start_read(struct mm_struct *mm,
}
rwsem_acquire_read(&vma->vmlock_dep_map, 0, 1, _RET_IP_);
+
+ /*
+ * If vma got attached to another mm from under us, that mm is not
+ * stable and can be freed in the narrow window after vma->vm_refcnt
+ * is dropped and before rcuwait_wake_up(mm) is called. Grab it before
+ * releasing vma->vm_refcnt.
+ */
+ if (unlikely(vma->vm_mm != mm)) {
+ /* Use a copy of vm_mm in case vma is freed after we drop vm_refcnt */
+ struct mm_struct *other_mm = vma->vm_mm;
+ /*
+ * __mmdrop() is a heavy operation and we don't need RCU
+ * protection here. Release RCU lock during these operations.
+ */
+ rcu_read_unlock();
+ mmgrab(other_mm);
+ vma_refcount_put(vma);
+ mmdrop(other_mm);
+ rcu_read_lock();
+ return NULL;
+ }
+
/*
* Overflow of vm_lock_seq/mm_lock_seq might produce false locked result.
* False unlocked result is impossible because we modify and check
diff --git a/mm/mmap_lock.c b/mm/mmap_lock.c
index 729fb7d0dd59..aa3bc42ecde0 100644
--- a/mm/mmap_lock.c
+++ b/mm/mmap_lock.c
@@ -164,8 +164,7 @@ struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm,
*/
/* Check if the vma we locked is the right one. */
- if (unlikely(vma->vm_mm != mm ||
- address < vma->vm_start || address >= vma->vm_end))
+ if (unlikely(address < vma->vm_start || address >= vma->vm_end))
goto inval_end_read;
rcu_read_unlock();
@@ -236,11 +235,8 @@ struct vm_area_struct *lock_next_vma(struct mm_struct *mm,
goto fallback;
}
- /*
- * Verify the vma we locked belongs to the same address space and it's
- * not behind of the last search position.
- */
- if (unlikely(vma->vm_mm != mm || from_addr >= vma->vm_end))
+ /* Verify the vma is not behind of the last search position. */
+ if (unlikely(from_addr >= vma->vm_end))
goto fallback_unlock;
/*
base-commit: c617a4dd7102e691fa0fb2bc4f6b369e37d7f509
--
2.50.1.487.gc89ff58d15-goog
The userprogs infrastructure does not expect clang being used with GNU ld
and in that case uses /usr/bin/ld for linking, not the configured $(LD).
This fallback is problematic as it will break when cross-compiling.
Mixing clang and GNU ld is used for example when building for SPARC64,
as ld.lld is not sufficient; see Documentation/kbuild/llvm.rst.
Relax the check around --ld-path so it gets used for all linkers.
Fixes: dfc1b168a8c4 ("kbuild: userprogs: use correct lld when linking through clang")
Cc: stable(a)vger.kernel.org
Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>
Reviewed-by: Nathan Chancellor <nathan(a)kernel.org>
---
Changes in v2:
- Use plain ifdef instead of ifneq
- Rebase onto v6.16
- Pick up review tag from Nathan
- Link to v1: https://lore.kernel.org/r/20250724-userprogs-clang-gnu-ld-v1-1-3d3d071e53a7…
---
Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 478f2004602da03c9039044e3288f24a13833cc7..7d24245d118c0e903119263b871d2e5c2759f48a 100644
--- a/Makefile
+++ b/Makefile
@@ -1134,7 +1134,7 @@ KBUILD_USERCFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CPPFLAGS) $(KBUILD
KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
# userspace programs are linked via the compiler, use the correct linker
-ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_LD_IS_LLD),yy)
+ifdef CONFIG_CC_IS_CLANG
KBUILD_USERLDFLAGS += --ld-path=$(LD)
endif
---
base-commit: 038d61fd642278bab63ee8ef722c50d10ab01e8f
change-id: 20250723-userprogs-clang-gnu-ld-7a1c16fc852d
Best regards,
--
Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>
UFS performance for < v4 controllers has reduced quite a bit in 6.16.
This series addresses this regression and brings numbers more or less
back to the previous level.
See patch 2 for some benchmark (fio) results.
Signed-off-by: André Draszik <andre.draszik(a)linaro.org>
---
Changes in v2:
- patch 1: new patch as suggested by Bart during v1 review
- patch 2: update commit message and some inline & kerneldoc comments
- patch 2: add missing jiffies.h include
- Link to v1: https://lore.kernel.org/r/20250724-ufshcd-hardirq-v1-1-6398a52f8f02@linaro.…
---
André Draszik (2):
scsi: ufs: core: complete polled requests also from interrupt context
scsi: ufs: core: move some irq handling back to hardirq (with time limit)
drivers/ufs/core/ufshcd.c | 211 +++++++++++++++++++++++++++++++++-------------
1 file changed, 152 insertions(+), 59 deletions(-)
---
base-commit: 58ba80c4740212c29a1cf9b48f588e60a7612209
change-id: 20250723-ufshcd-hardirq-c7326f642e56
Best regards,
--
André Draszik <andre.draszik(a)linaro.org>