The patch below does not apply to the 5.4-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-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x f965d111e68f4a993cc44d487d416e3d954eea11
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101656-peso-landfill-d499@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f965d111e68f4a993cc44d487d416e3d954eea11 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki(a)intel.com>
Date: Fri, 26 Sep 2025 12:19:41 +0200
Subject: [PATCH] cpufreq: CPPC: Avoid using CPUFREQ_ETERNAL as transition
delay
If cppc_get_transition_latency() returns CPUFREQ_ETERNAL to indicate a
failure to retrieve the transition latency value from the platform
firmware, the CPPC cpufreq driver will use that value (converted to
microseconds) as the policy transition delay, but it is way too large
for any practical use.
Address this by making the driver use the cpufreq's default
transition latency value (in microseconds) as the transition delay
if CPUFREQ_ETERNAL is returned by cppc_get_transition_latency().
Fixes: d4f3388afd48 ("cpufreq / CPPC: Set platform specific transition_delay_us")
Cc: 5.19+ <stable(a)vger.kernel.org> # 5.19
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com>
Reviewed-by: Mario Limonciello (AMD) <superm1(a)kernel.org>
Reviewed-by: Jie Zhan <zhanjie9(a)hisilicon.com>
Acked-by: Viresh Kumar <viresh.kumar(a)linaro.org>
Reviewed-by: Qais Yousef <qyousef(a)layalina.io>
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 12de0ac7bbaf..b71946937c52 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -308,6 +308,16 @@ static int cppc_verify_policy(struct cpufreq_policy_data *policy)
return 0;
}
+static unsigned int __cppc_cpufreq_get_transition_delay_us(unsigned int cpu)
+{
+ unsigned int transition_latency_ns = cppc_get_transition_latency(cpu);
+
+ if (transition_latency_ns == CPUFREQ_ETERNAL)
+ return CPUFREQ_DEFAULT_TRANSITION_LATENCY_NS / NSEC_PER_USEC;
+
+ return transition_latency_ns / NSEC_PER_USEC;
+}
+
/*
* The PCC subspace describes the rate at which platform can accept commands
* on the shared PCC channel (including READs which do not count towards freq
@@ -330,12 +340,12 @@ static unsigned int cppc_cpufreq_get_transition_delay_us(unsigned int cpu)
return 10000;
}
}
- return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
+ return __cppc_cpufreq_get_transition_delay_us(cpu);
}
#else
static unsigned int cppc_cpufreq_get_transition_delay_us(unsigned int cpu)
{
- return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
+ return __cppc_cpufreq_get_transition_delay_us(cpu);
}
#endif
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 f965d111e68f4a993cc44d487d416e3d954eea11
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101655-hardhead-variably-b7de@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f965d111e68f4a993cc44d487d416e3d954eea11 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki(a)intel.com>
Date: Fri, 26 Sep 2025 12:19:41 +0200
Subject: [PATCH] cpufreq: CPPC: Avoid using CPUFREQ_ETERNAL as transition
delay
If cppc_get_transition_latency() returns CPUFREQ_ETERNAL to indicate a
failure to retrieve the transition latency value from the platform
firmware, the CPPC cpufreq driver will use that value (converted to
microseconds) as the policy transition delay, but it is way too large
for any practical use.
Address this by making the driver use the cpufreq's default
transition latency value (in microseconds) as the transition delay
if CPUFREQ_ETERNAL is returned by cppc_get_transition_latency().
Fixes: d4f3388afd48 ("cpufreq / CPPC: Set platform specific transition_delay_us")
Cc: 5.19+ <stable(a)vger.kernel.org> # 5.19
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com>
Reviewed-by: Mario Limonciello (AMD) <superm1(a)kernel.org>
Reviewed-by: Jie Zhan <zhanjie9(a)hisilicon.com>
Acked-by: Viresh Kumar <viresh.kumar(a)linaro.org>
Reviewed-by: Qais Yousef <qyousef(a)layalina.io>
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 12de0ac7bbaf..b71946937c52 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -308,6 +308,16 @@ static int cppc_verify_policy(struct cpufreq_policy_data *policy)
return 0;
}
+static unsigned int __cppc_cpufreq_get_transition_delay_us(unsigned int cpu)
+{
+ unsigned int transition_latency_ns = cppc_get_transition_latency(cpu);
+
+ if (transition_latency_ns == CPUFREQ_ETERNAL)
+ return CPUFREQ_DEFAULT_TRANSITION_LATENCY_NS / NSEC_PER_USEC;
+
+ return transition_latency_ns / NSEC_PER_USEC;
+}
+
/*
* The PCC subspace describes the rate at which platform can accept commands
* on the shared PCC channel (including READs which do not count towards freq
@@ -330,12 +340,12 @@ static unsigned int cppc_cpufreq_get_transition_delay_us(unsigned int cpu)
return 10000;
}
}
- return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
+ return __cppc_cpufreq_get_transition_delay_us(cpu);
}
#else
static unsigned int cppc_cpufreq_get_transition_delay_us(unsigned int cpu)
{
- return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
+ return __cppc_cpufreq_get_transition_delay_us(cpu);
}
#endif
When adding dependencies with drm_sched_job_add_dependency(), that
function consumes the fence reference both on success and failure, so in
the latter case the dma_fence_put() on the error path (xarray failed to
expand) is a double free.
Interestingly this bug appears to have been present ever since
commit ebd5f74255b9 ("drm/sched: Add dependency tracking"), since the code
back then looked like this:
drm_sched_job_add_implicit_dependencies():
...
for (i = 0; i < fence_count; i++) {
ret = drm_sched_job_add_dependency(job, fences[i]);
if (ret)
break;
}
for (; i < fence_count; i++)
dma_fence_put(fences[i]);
Which means for the failing 'i' the dma_fence_put was already a double
free. Possibly there were no users at that time, or the test cases were
insufficient to hit it.
The bug was then only noticed and fixed after
commit 9c2ba265352a ("drm/scheduler: use new iterator in drm_sched_job_add_implicit_dependencies v2")
landed, with its fixup of
commit 4eaf02d6076c ("drm/scheduler: fix drm_sched_job_add_implicit_dependencies").
At that point it was a slightly different flavour of a double free, which
commit 963d0b356935 ("drm/scheduler: fix drm_sched_job_add_implicit_dependencies harder")
noticed and attempted to fix.
But it only moved the double free from happening inside the
drm_sched_job_add_dependency(), when releasing the reference not yet
obtained, to the caller, when releasing the reference already released by
the former in the failure case.
As such it is not easy to identify the right target for the fixes tag so
lets keep it simple and just continue the chain.
While fixing we also improve the comment and explain the reason for taking
the reference and not dropping it.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin(a)igalia.com>
Fixes: 963d0b356935 ("drm/scheduler: fix drm_sched_job_add_implicit_dependencies harder")
Reported-by: Dan Carpenter <dan.carpenter(a)linaro.org>
Closes: https://lore.kernel.org/dri-devel/aNFbXq8OeYl3QSdm@stanley.mountain/
Cc: Christian König <christian.koenig(a)amd.com>
Cc: Rob Clark <robdclark(a)chromium.org>
Cc: Daniel Vetter <daniel.vetter(a)ffwll.ch>
Cc: Matthew Brost <matthew.brost(a)intel.com>
Cc: Danilo Krummrich <dakr(a)kernel.org>
Cc: Philipp Stanner <phasta(a)kernel.org>
Cc: "Christian König" <ckoenig.leichtzumerken(a)gmail.com>
Cc: dri-devel(a)lists.freedesktop.org
Cc: <stable(a)vger.kernel.org> # v5.16+
---
v2:
* Re-arrange commit text so discussion around sentences starting with
capital letters in all cases can be avoided.
* Keep double return for now.
* Improved comment instead of dropping it.
v3:
* Commit SHA formatting in the commit message.
---
drivers/gpu/drm/scheduler/sched_main.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 46119aacb809..c39f0245e3a9 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -965,13 +965,14 @@ int drm_sched_job_add_resv_dependencies(struct drm_sched_job *job,
dma_resv_assert_held(resv);
dma_resv_for_each_fence(&cursor, resv, usage, fence) {
- /* Make sure to grab an additional ref on the added fence */
- dma_fence_get(fence);
- ret = drm_sched_job_add_dependency(job, fence);
- if (ret) {
- dma_fence_put(fence);
+ /*
+ * As drm_sched_job_add_dependency always consumes the fence
+ * reference (even when it fails), and dma_resv_for_each_fence
+ * is not obtaining one, we need to grab one before calling.
+ */
+ ret = drm_sched_job_add_dependency(job, dma_fence_get(fence));
+ if (ret)
return ret;
- }
}
return 0;
}
--
2.48.0
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 195a1b7d8388c0ec2969a39324feb8bebf9bb907
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101634-riveter-crust-f6b3@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 195a1b7d8388c0ec2969a39324feb8bebf9bb907 Mon Sep 17 00:00:00 2001
From: Yang Shi <yang(a)os.amperecomputing.com>
Date: Thu, 18 Sep 2025 09:23:49 -0700
Subject: [PATCH] arm64: kprobes: call set_memory_rox() for kprobe page
The kprobe page is allocated by execmem allocator with ROX permission.
It needs to call set_memory_rox() to set proper permission for the
direct map too. It was missed.
Fixes: 10d5e97c1bf8 ("arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Yang Shi <yang(a)os.amperecomputing.com>
Reviewed-by: Catalin Marinas <catalin.marinas(a)arm.com>
Signed-off-by: Will Deacon <will(a)kernel.org>
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 0c5d408afd95..8ab6104a4883 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -10,6 +10,7 @@
#define pr_fmt(fmt) "kprobes: " fmt
+#include <linux/execmem.h>
#include <linux/extable.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
@@ -41,6 +42,17 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
static void __kprobes
post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
+void *alloc_insn_page(void)
+{
+ void *addr;
+
+ addr = execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE);
+ if (!addr)
+ return NULL;
+ set_memory_rox((unsigned long)addr, 1);
+ return addr;
+}
+
static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
{
kprobe_opcode_t *addr = p->ainsn.xol_insn;
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 195a1b7d8388c0ec2969a39324feb8bebf9bb907
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101608-fastball-thaw-dc90@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 195a1b7d8388c0ec2969a39324feb8bebf9bb907 Mon Sep 17 00:00:00 2001
From: Yang Shi <yang(a)os.amperecomputing.com>
Date: Thu, 18 Sep 2025 09:23:49 -0700
Subject: [PATCH] arm64: kprobes: call set_memory_rox() for kprobe page
The kprobe page is allocated by execmem allocator with ROX permission.
It needs to call set_memory_rox() to set proper permission for the
direct map too. It was missed.
Fixes: 10d5e97c1bf8 ("arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Yang Shi <yang(a)os.amperecomputing.com>
Reviewed-by: Catalin Marinas <catalin.marinas(a)arm.com>
Signed-off-by: Will Deacon <will(a)kernel.org>
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 0c5d408afd95..8ab6104a4883 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -10,6 +10,7 @@
#define pr_fmt(fmt) "kprobes: " fmt
+#include <linux/execmem.h>
#include <linux/extable.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
@@ -41,6 +42,17 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
static void __kprobes
post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
+void *alloc_insn_page(void)
+{
+ void *addr;
+
+ addr = execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE);
+ if (!addr)
+ return NULL;
+ set_memory_rox((unsigned long)addr, 1);
+ return addr;
+}
+
static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
{
kprobe_opcode_t *addr = p->ainsn.xol_insn;
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 f5225a34bd8f9f64eec37f6ae1461289aaa3eb86
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101623-error-attain-05f5@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f5225a34bd8f9f64eec37f6ae1461289aaa3eb86 Mon Sep 17 00:00:00 2001
From: Sumit Kumar <sumit.kumar(a)oss.qualcomm.com>
Date: Wed, 10 Sep 2025 18:11:09 +0530
Subject: [PATCH] bus: mhi: ep: Fix chained transfer handling in read path
The mhi_ep_read_channel function incorrectly assumes the End of Transfer
(EOT) bit is present for each packet in a chained transactions, causing
it to advance mhi_chan->rd_offset beyond wr_offset during host-to-device
transfers when EOT has not yet arrived. This leads to access of unmapped
host memory, causing IOMMU faults and processing of stale TREs.
Modify the loop condition to ensure mhi_queue is not empty, allowing the
function to process only valid TREs up to the current write pointer to
prevent premature reads and ensure safe traversal of chained TREs.
Due to this change, buf_left needs to be removed from the while loop
condition to avoid exiting prematurely before reading the ring completely,
and also remove write_offset since it will always be zero because the new
cache buffer is allocated every time.
Fixes: 5301258899773 ("bus: mhi: ep: Add support for reading from the host")
Co-developed-by: Akhil Vinod <akhil.vinod(a)oss.qualcomm.com>
Signed-off-by: Akhil Vinod <akhil.vinod(a)oss.qualcomm.com>
Signed-off-by: Sumit Kumar <sumit.kumar(a)oss.qualcomm.com>
[mani: reworded description slightly]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam(a)oss.qualcomm.com>
Reviewed-by: Krishna Chaitanya Chundru <krishna.chundru(a)oss.qualcomm.com>
Cc: stable(a)vger.kernel.org
Link: https://patch.msgid.link/20250910-final_chained-v3-1-ec77c9d88ace@oss.qualc…
diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index b3eafcf2a2c5..cdea24e92919 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -403,17 +403,13 @@ static int mhi_ep_read_channel(struct mhi_ep_cntrl *mhi_cntrl,
{
struct mhi_ep_chan *mhi_chan = &mhi_cntrl->mhi_chan[ring->ch_id];
struct device *dev = &mhi_cntrl->mhi_dev->dev;
- size_t tr_len, read_offset, write_offset;
+ size_t tr_len, read_offset;
struct mhi_ep_buf_info buf_info = {};
u32 len = MHI_EP_DEFAULT_MTU;
struct mhi_ring_element *el;
- bool tr_done = false;
void *buf_addr;
- u32 buf_left;
int ret;
- buf_left = len;
-
do {
/* Don't process the transfer ring if the channel is not in RUNNING state */
if (mhi_chan->state != MHI_CH_STATE_RUNNING) {
@@ -426,24 +422,23 @@ static int mhi_ep_read_channel(struct mhi_ep_cntrl *mhi_cntrl,
/* Check if there is data pending to be read from previous read operation */
if (mhi_chan->tre_bytes_left) {
dev_dbg(dev, "TRE bytes remaining: %u\n", mhi_chan->tre_bytes_left);
- tr_len = min(buf_left, mhi_chan->tre_bytes_left);
+ tr_len = min(len, mhi_chan->tre_bytes_left);
} else {
mhi_chan->tre_loc = MHI_TRE_DATA_GET_PTR(el);
mhi_chan->tre_size = MHI_TRE_DATA_GET_LEN(el);
mhi_chan->tre_bytes_left = mhi_chan->tre_size;
- tr_len = min(buf_left, mhi_chan->tre_size);
+ tr_len = min(len, mhi_chan->tre_size);
}
read_offset = mhi_chan->tre_size - mhi_chan->tre_bytes_left;
- write_offset = len - buf_left;
buf_addr = kmem_cache_zalloc(mhi_cntrl->tre_buf_cache, GFP_KERNEL);
if (!buf_addr)
return -ENOMEM;
buf_info.host_addr = mhi_chan->tre_loc + read_offset;
- buf_info.dev_addr = buf_addr + write_offset;
+ buf_info.dev_addr = buf_addr;
buf_info.size = tr_len;
buf_info.cb = mhi_ep_read_completion;
buf_info.cb_buf = buf_addr;
@@ -459,16 +454,12 @@ static int mhi_ep_read_channel(struct mhi_ep_cntrl *mhi_cntrl,
goto err_free_buf_addr;
}
- buf_left -= tr_len;
mhi_chan->tre_bytes_left -= tr_len;
- if (!mhi_chan->tre_bytes_left) {
- if (MHI_TRE_DATA_GET_IEOT(el))
- tr_done = true;
-
+ if (!mhi_chan->tre_bytes_left)
mhi_chan->rd_offset = (mhi_chan->rd_offset + 1) % ring->ring_size;
- }
- } while (buf_left && !tr_done);
+ /* Read until the some buffer is left or the ring becomes not empty */
+ } while (!mhi_ep_queue_is_empty(mhi_chan->mhi_dev, DMA_TO_DEVICE));
return 0;
@@ -502,15 +493,11 @@ static int mhi_ep_process_ch_ring(struct mhi_ep_ring *ring)
mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
} else {
/* UL channel */
- do {
- ret = mhi_ep_read_channel(mhi_cntrl, ring);
- if (ret < 0) {
- dev_err(&mhi_chan->mhi_dev->dev, "Failed to read channel\n");
- return ret;
- }
-
- /* Read until the ring becomes empty */
- } while (!mhi_ep_queue_is_empty(mhi_chan->mhi_dev, DMA_TO_DEVICE));
+ ret = mhi_ep_read_channel(mhi_cntrl, ring);
+ if (ret < 0) {
+ dev_err(&mhi_chan->mhi_dev->dev, "Failed to read channel\n");
+ return ret;
+ }
}
return 0;
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 6eb350a2233100a283f882c023e5ad426d0ed63b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101555-untitled-sighing-27f5@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 6eb350a2233100a283f882c023e5ad426d0ed63b Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx(a)linutronix.de>
Date: Wed, 13 Aug 2025 17:02:30 +0200
Subject: [PATCH] rseq: Protect event mask against membarrier IPI
rseq_need_restart() reads and clears task::rseq_event_mask with preemption
disabled to guard against the scheduler.
But membarrier() uses an IPI and sets the PREEMPT bit in the event mask
from the IPI, which leaves that RMW operation unprotected.
Use guard(irq) if CONFIG_MEMBARRIER is enabled to fix that.
Fixes: 2a36ab717e8f ("rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ")
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Reviewed-by: Boqun Feng <boqun.feng(a)gmail.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
Cc: stable(a)vger.kernel.org
diff --git a/include/linux/rseq.h b/include/linux/rseq.h
index bc8af3eb5598..1fbeb61babeb 100644
--- a/include/linux/rseq.h
+++ b/include/linux/rseq.h
@@ -7,6 +7,12 @@
#include <linux/preempt.h>
#include <linux/sched.h>
+#ifdef CONFIG_MEMBARRIER
+# define RSEQ_EVENT_GUARD irq
+#else
+# define RSEQ_EVENT_GUARD preempt
+#endif
+
/*
* Map the event mask on the user-space ABI enum rseq_cs_flags
* for direct mask checks.
@@ -41,9 +47,8 @@ static inline void rseq_handle_notify_resume(struct ksignal *ksig,
static inline void rseq_signal_deliver(struct ksignal *ksig,
struct pt_regs *regs)
{
- preempt_disable();
- __set_bit(RSEQ_EVENT_SIGNAL_BIT, ¤t->rseq_event_mask);
- preempt_enable();
+ scoped_guard(RSEQ_EVENT_GUARD)
+ __set_bit(RSEQ_EVENT_SIGNAL_BIT, ¤t->rseq_event_mask);
rseq_handle_notify_resume(ksig, regs);
}
diff --git a/kernel/rseq.c b/kernel/rseq.c
index b7a1ec327e81..2452b7366b00 100644
--- a/kernel/rseq.c
+++ b/kernel/rseq.c
@@ -342,12 +342,12 @@ static int rseq_need_restart(struct task_struct *t, u32 cs_flags)
/*
* Load and clear event mask atomically with respect to
- * scheduler preemption.
+ * scheduler preemption and membarrier IPIs.
*/
- preempt_disable();
- event_mask = t->rseq_event_mask;
- t->rseq_event_mask = 0;
- preempt_enable();
+ scoped_guard(RSEQ_EVENT_GUARD) {
+ event_mask = t->rseq_event_mask;
+ t->rseq_event_mask = 0;
+ }
return !!event_mask;
}
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 e8c84e2082e69335f66c8ade4895e80ec270d7c4
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101533-mutt-routing-a332@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e8c84e2082e69335f66c8ade4895e80ec270d7c4 Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner(a)kernel.org>
Date: Fri, 19 Sep 2025 17:03:51 +0200
Subject: [PATCH] statmount: don't call path_put() under namespace semaphore
Massage statmount() and make sure we don't call path_put() under the
namespace semaphore. If we put the last reference we're fscked.
Fixes: 46eae99ef733 ("add statmount(2) syscall")
Cc: stable(a)vger.kernel.org # v6.8+
Signed-off-by: Christian Brauner <brauner(a)kernel.org>
diff --git a/fs/namespace.c b/fs/namespace.c
index ba3e5215b636..993983a76853 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -5708,7 +5708,6 @@ static int grab_requested_root(struct mnt_namespace *ns, struct path *root)
static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id,
struct mnt_namespace *ns)
{
- struct path root __free(path_put) = {};
struct mount *m;
int err;
@@ -5720,7 +5719,7 @@ static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id,
if (!s->mnt)
return -ENOENT;
- err = grab_requested_root(ns, &root);
+ err = grab_requested_root(ns, &s->root);
if (err)
return err;
@@ -5729,7 +5728,7 @@ static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id,
* mounts to show users.
*/
m = real_mount(s->mnt);
- if (!is_path_reachable(m, m->mnt.mnt_root, &root) &&
+ if (!is_path_reachable(m, m->mnt.mnt_root, &s->root) &&
!ns_capable_noaudit(ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
@@ -5737,8 +5736,6 @@ static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id,
if (err)
return err;
- s->root = root;
-
/*
* Note that mount properties in mnt->mnt_flags, mnt->mnt_idmap
* can change concurrently as we only hold the read-side of the
@@ -5960,6 +5957,7 @@ SYSCALL_DEFINE4(statmount, const struct mnt_id_req __user *, req,
if (!ret)
ret = copy_statmount_to_user(ks);
kvfree(ks->seq.buf);
+ path_put(&ks->root);
if (retry_statmount(ret, &seq_size))
goto retry;
return ret;