The patch below does not apply to the 6.16-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-6.16.y
git checkout FETCH_HEAD
git cherry-pick -x 8dc1812b5b3a42311d28eb385eed88e2053ad3cb
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025082118-unhook-drinking-9926@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8dc1812b5b3a42311d28eb385eed88e2053ad3cb Mon Sep 17 00:00:00 2001
From: Matthew Brost <matthew.brost(a)intel.com>
Date: Mon, 12 May 2025 06:54:57 -0700
Subject: [PATCH] drm/gpusvm: Add timeslicing support to GPU SVM
Add timeslicing support to GPU SVM which will guarantee the GPU a
minimum execution time on piece of physical memory before migration back
to CPU. Intended to implement strict migration policies which require
memory to be in a certain placement for correct execution.
Required for shared CPU and GPU atomics on certain devices.
Fixes: 99624bdff867 ("drm/gpusvm: Add support for GPU Shared Virtual Memory")
Cc: stable(a)vger.kernel.org
Signed-off-by: Matthew Brost <matthew.brost(a)intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray(a)intel.com>
Link: https://lore.kernel.org/r/20250512135500.1405019-4-matthew.brost@intel.com
diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c
index 41f6616bcf76..4b2f32889f00 100644
--- a/drivers/gpu/drm/drm_gpusvm.c
+++ b/drivers/gpu/drm/drm_gpusvm.c
@@ -1783,6 +1783,8 @@ int drm_gpusvm_migrate_to_devmem(struct drm_gpusvm *gpusvm,
goto err_finalize;
/* Upon success bind devmem allocation to range and zdd */
+ devmem_allocation->timeslice_expiration = get_jiffies_64() +
+ msecs_to_jiffies(ctx->timeslice_ms);
zdd->devmem_allocation = devmem_allocation; /* Owns ref */
err_finalize:
@@ -2003,6 +2005,13 @@ static int __drm_gpusvm_migrate_to_ram(struct vm_area_struct *vas,
void *buf;
int i, err = 0;
+ if (page) {
+ zdd = page->zone_device_data;
+ if (time_before64(get_jiffies_64(),
+ zdd->devmem_allocation->timeslice_expiration))
+ return 0;
+ }
+
start = ALIGN_DOWN(fault_addr, size);
end = ALIGN(fault_addr + 1, size);
diff --git a/include/drm/drm_gpusvm.h b/include/drm/drm_gpusvm.h
index 653d48dbe1c1..eaf704d3d05e 100644
--- a/include/drm/drm_gpusvm.h
+++ b/include/drm/drm_gpusvm.h
@@ -89,6 +89,7 @@ struct drm_gpusvm_devmem_ops {
* @ops: Pointer to the operations structure for GPU SVM device memory
* @dpagemap: The struct drm_pagemap of the pages this allocation belongs to.
* @size: Size of device memory allocation
+ * @timeslice_expiration: Timeslice expiration in jiffies
*/
struct drm_gpusvm_devmem {
struct device *dev;
@@ -97,6 +98,7 @@ struct drm_gpusvm_devmem {
const struct drm_gpusvm_devmem_ops *ops;
struct drm_pagemap *dpagemap;
size_t size;
+ u64 timeslice_expiration;
};
/**
@@ -295,6 +297,8 @@ struct drm_gpusvm {
* @check_pages_threshold: Check CPU pages for present if chunk is less than or
* equal to threshold. If not present, reduce chunk
* size.
+ * @timeslice_ms: The timeslice MS which in minimum time a piece of memory
+ * remains with either exclusive GPU or CPU access.
* @in_notifier: entering from a MMU notifier
* @read_only: operating on read-only memory
* @devmem_possible: possible to use device memory
@@ -304,6 +308,7 @@ struct drm_gpusvm {
*/
struct drm_gpusvm_ctx {
unsigned long check_pages_threshold;
+ unsigned long timeslice_ms;
unsigned int in_notifier :1;
unsigned int read_only :1;
unsigned int devmem_possible :1;
The patch below does not apply to the 6.16-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-6.16.y
git checkout FETCH_HEAD
git cherry-pick -x 8a9b978ebd47df9e0694c34748c2d6fa0c31eb4d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025082112-ecologist-starry-b438@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8a9b978ebd47df9e0694c34748c2d6fa0c31eb4d Mon Sep 17 00:00:00 2001
From: Himal Prasad Ghimiray <himal.prasad.ghimiray(a)intel.com>
Date: Mon, 12 May 2025 06:54:55 -0700
Subject: [PATCH] drm/gpusvm: Introduce devmem_only flag for allocation
This commit adds a new flag, devmem_only, to the drm_gpusvm structure. The
purpose of this flag is to ensure that the get_pages function allocates
memory exclusively from the device's memory. If the allocation from
device memory fails, the function will return an -EFAULT error.
Required for shared CPU and GPU atomics on certain devices.
v3:
- s/vram_only/devmem_only/
Fixes: 99624bdff867 ("drm/gpusvm: Add support for GPU Shared Virtual Memory")
Cc: stable(a)vger.kernel.org
Signed-off-by: Matthew Brost <matthew.brost(a)intel.com>
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray(a)intel.com>
Reviewed-by: Matthew Brost <matthew.brost(a)intel.com>
Link: https://lore.kernel.org/r/20250512135500.1405019-2-matthew.brost@intel.com
diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c
index de424e670995..a58d03e6cac2 100644
--- a/drivers/gpu/drm/drm_gpusvm.c
+++ b/drivers/gpu/drm/drm_gpusvm.c
@@ -1454,6 +1454,11 @@ int drm_gpusvm_range_get_pages(struct drm_gpusvm *gpusvm,
goto err_unmap;
}
+ if (ctx->devmem_only) {
+ err = -EFAULT;
+ goto err_unmap;
+ }
+
addr = dma_map_page(gpusvm->drm->dev,
page, 0,
PAGE_SIZE << order,
diff --git a/include/drm/drm_gpusvm.h b/include/drm/drm_gpusvm.h
index df120b4d1f83..9fd25fc880a4 100644
--- a/include/drm/drm_gpusvm.h
+++ b/include/drm/drm_gpusvm.h
@@ -286,6 +286,7 @@ struct drm_gpusvm {
* @in_notifier: entering from a MMU notifier
* @read_only: operating on read-only memory
* @devmem_possible: possible to use device memory
+ * @devmem_only: use only device memory
*
* Context that is DRM GPUSVM is operating in (i.e. user arguments).
*/
@@ -294,6 +295,7 @@ struct drm_gpusvm_ctx {
unsigned int in_notifier :1;
unsigned int read_only :1;
unsigned int devmem_possible :1;
+ unsigned int devmem_only :1;
};
int drm_gpusvm_init(struct drm_gpusvm *gpusvm,
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 ccfb15b8158c11a8304204aeac354c7b1cfb18a3
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025082138-spew-mardi-8760@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ccfb15b8158c11a8304204aeac354c7b1cfb18a3 Mon Sep 17 00:00:00 2001
From: "Vodapalli, Ravi Kumar" <ravi.kumar.vodapalli(a)intel.com>
Date: Fri, 4 Jul 2025 16:05:27 +0530
Subject: [PATCH] drm/xe/bmg: Add one additional PCI ID
One additional PCI ID is added in Bspec for BMG, Add it so that
driver recognizes this device with this new ID.
Bspec: 68090
Cc: stable(a)vger.kernel.org # v6.12+
Signed-off-by: Vodapalli, Ravi Kumar <ravi.kumar.vodapalli(a)intel.com>
Reviewed-by: Shekhar Chauhan <shekhar.chauhan(a)intel.com>
Acked-by: Matthew Auld <matthew.auld(a)intel.com>
Signed-off-by: Matthew Auld <matthew.auld(a)intel.com>
Link: https://lore.kernel.org/r/20250704103527.100178-1-ravi.kumar.vodapalli@inte…
diff --git a/include/drm/intel/pciids.h b/include/drm/intel/pciids.h
index a0180d10e260..76f8d26f9cc9 100644
--- a/include/drm/intel/pciids.h
+++ b/include/drm/intel/pciids.h
@@ -846,6 +846,7 @@
/* BMG */
#define INTEL_BMG_IDS(MACRO__, ...) \
MACRO__(0xE202, ## __VA_ARGS__), \
+ MACRO__(0xE209, ## __VA_ARGS__), \
MACRO__(0xE20B, ## __VA_ARGS__), \
MACRO__(0xE20C, ## __VA_ARGS__), \
MACRO__(0xE20D, ## __VA_ARGS__), \
The patch below does not apply to the 6.16-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-6.16.y
git checkout FETCH_HEAD
git cherry-pick -x 017ef1228d735965419ff118fe1b89089e772c42
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025082107-shortcut-trough-dbf3@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 017ef1228d735965419ff118fe1b89089e772c42 Mon Sep 17 00:00:00 2001
From: Shuicheng Lin <shuicheng.lin(a)intel.com>
Date: Mon, 7 Jul 2025 00:49:14 +0000
Subject: [PATCH] drm/xe: Release runtime pm for error path of
xe_devcoredump_read()
xe_pm_runtime_put() is missed to be called for the error path in
xe_devcoredump_read().
Add function description comments for xe_devcoredump_read() to help
understand it.
v2: more detail function comments and refine goto logic (Matt)
Fixes: c4a2e5f865b7 ("drm/xe: Add devcoredump chunking")
Cc: stable(a)vger.kernel.org
Reviewed-by: Matthew Brost <matthew.brost(a)intel.com>
Signed-off-by: Shuicheng Lin <shuicheng.lin(a)intel.com>
Signed-off-by: Matthew Brost <matthew.brost(a)intel.com>
Link: https://lore.kernel.org/r/20250707004911.3502904-6-shuicheng.lin@intel.com
diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
index 94625010abc4..203e3038cc81 100644
--- a/drivers/gpu/drm/xe/xe_devcoredump.c
+++ b/drivers/gpu/drm/xe/xe_devcoredump.c
@@ -171,14 +171,32 @@ static void xe_devcoredump_snapshot_free(struct xe_devcoredump_snapshot *ss)
#define XE_DEVCOREDUMP_CHUNK_MAX (SZ_512M + SZ_1G)
+/**
+ * xe_devcoredump_read() - Read data from the Xe device coredump snapshot
+ * @buffer: Destination buffer to copy the coredump data into
+ * @offset: Offset in the coredump data to start reading from
+ * @count: Number of bytes to read
+ * @data: Pointer to the xe_devcoredump structure
+ * @datalen: Length of the data (unused)
+ *
+ * Reads a chunk of the coredump snapshot data into the provided buffer.
+ * If the devcoredump is smaller than 1.5 GB (XE_DEVCOREDUMP_CHUNK_MAX),
+ * it is read directly from a pre-written buffer. For larger devcoredumps,
+ * the pre-written buffer must be periodically repopulated from the snapshot
+ * state due to kmalloc size limitations.
+ *
+ * Return: Number of bytes copied on success, or a negative error code on failure.
+ */
static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
size_t count, void *data, size_t datalen)
{
struct xe_devcoredump *coredump = data;
struct xe_devcoredump_snapshot *ss;
- ssize_t byte_copied;
+ ssize_t byte_copied = 0;
u32 chunk_offset;
ssize_t new_chunk_position;
+ bool pm_needed = false;
+ int ret = 0;
if (!coredump)
return -ENODEV;
@@ -188,20 +206,19 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
/* Ensure delayed work is captured before continuing */
flush_work(&ss->work);
- if (ss->read.size > XE_DEVCOREDUMP_CHUNK_MAX)
+ pm_needed = ss->read.size > XE_DEVCOREDUMP_CHUNK_MAX;
+ if (pm_needed)
xe_pm_runtime_get(gt_to_xe(ss->gt));
mutex_lock(&coredump->lock);
if (!ss->read.buffer) {
- mutex_unlock(&coredump->lock);
- return -ENODEV;
+ ret = -ENODEV;
+ goto unlock;
}
- if (offset >= ss->read.size) {
- mutex_unlock(&coredump->lock);
- return 0;
- }
+ if (offset >= ss->read.size)
+ goto unlock;
new_chunk_position = div_u64_rem(offset,
XE_DEVCOREDUMP_CHUNK_MAX,
@@ -221,12 +238,13 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
ss->read.size - offset;
memcpy(buffer, ss->read.buffer + chunk_offset, byte_copied);
+unlock:
mutex_unlock(&coredump->lock);
- if (ss->read.size > XE_DEVCOREDUMP_CHUNK_MAX)
+ if (pm_needed)
xe_pm_runtime_put(gt_to_xe(ss->gt));
- return byte_copied;
+ return byte_copied ? byte_copied : ret;
}
static void xe_devcoredump_free(void *data)
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 1d60796a62f327cd9e0a6a0865ded7656d2c67f9
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025082144-poplar-glare-2f1c@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 1d60796a62f327cd9e0a6a0865ded7656d2c67f9 Mon Sep 17 00:00:00 2001
From: Lukas Wunner <lukas(a)wunner.de>
Date: Sun, 13 Jul 2025 16:31:02 +0200
Subject: [PATCH] PCI/portdrv: Use is_pciehp instead of is_hotplug_bridge
The PCIe port driver erroneously creates a subdevice for hotplug on ACPI
slots which are handled by the ACPI hotplug driver.
Avoid by checking the is_pciehp flag instead of is_hotplug_bridge when
deciding whether to create a subdevice. The latter encompasses ACPI slots
whereas the former doesn't.
The superfluous subdevice has no real negative impact, it occupies memory
and interrupt resources but otherwise just sits there waiting for
interrupts from the slot that are never signaled.
Fixes: f8415222837b ("PCI: Use cached copy of PCI_EXP_SLTCAP_HPC bit")
Signed-off-by: Lukas Wunner <lukas(a)wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas(a)google.com>
Cc: stable(a)vger.kernel.org # v4.7+
Link: https://patch.msgid.link/40d5a5fe8d40595d505949c620a067fa110ee85e.175239010…
diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c
index e8318fd5f6ed..d1b68c18444f 100644
--- a/drivers/pci/pcie/portdrv.c
+++ b/drivers/pci/pcie/portdrv.c
@@ -220,7 +220,7 @@ static int get_port_device_capability(struct pci_dev *dev)
struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
int services = 0;
- if (dev->is_hotplug_bridge &&
+ if (dev->is_pciehp &&
(pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM) &&
(pcie_ports_native || host->native_pcie_hotplug)) {
From: NeilBrown <neil(a)brown.name>
commit 5f1c8965e748c150d580a2ea8fbee1bd80d07a24 upstream.
ovl_create_temp() treats "workdir" as a parent in which it creates an
object so it should use I_MUTEX_PARENT.
Prior to the commit identified below the lock was taken by the caller
which sometimes used I_MUTEX_PARENT and sometimes used I_MUTEX_NORMAL.
The use of I_MUTEX_NORMAL was incorrect but unfortunately copied into
ovl_create_temp().
Note to backporters: This patch only applies after the last Fixes given
below (post v6.16). To fix the bug in v6.7 and later the
inode_lock() call in ovl_copy_up_workdir() needs to nest using
I_MUTEX_PARENT.
[Amir: backport to v6.16 when lock was taken by the callers]
Link: https://lore.kernel.org/all/67a72070.050a0220.3d72c.0022.GAE@google.com/
Cc: stable(a)vger.kernel.org
Reported-by: syzbot+7836a68852a10ec3d790(a)syzkaller.appspotmail.com
Tested-by: syzbot+7836a68852a10ec3d790(a)syzkaller.appspotmail.com
Fixes: c63e56a4a652 ("ovl: do not open/llseek lower file with upper sb_writers held")
Fixes: d2c995581c7c ("ovl: Call ovl_create_temp() without lock held.")
Signed-off-by: NeilBrown <neil(a)brown.name>
Signed-off-by: Amir Goldstein <amir73il(a)gmail.com>
---
fs/overlayfs/copy_up.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index d7310fcf38881..c2263148ff20a 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -779,7 +779,7 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
return err;
ovl_start_write(c->dentry);
- inode_lock(wdir);
+ inode_lock_nested(wdir, I_MUTEX_PARENT);
temp = ovl_create_temp(ofs, c->workdir, &cattr);
inode_unlock(wdir);
ovl_end_write(c->dentry);
--
2.50.1
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 cb22f247f371bd206a88cf0e0c05d80b8b62fb26
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025082133-resubmit-starlit-d1e3@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From cb22f247f371bd206a88cf0e0c05d80b8b62fb26 Mon Sep 17 00:00:00 2001
From: John David Anglin <dave.anglin(a)bell.net>
Date: Mon, 21 Jul 2025 15:13:42 -0400
Subject: [PATCH] parisc: Update comments in make_insert_tlb
The following testcase exposed a problem with our read access checks
in get_user() and raw_copy_from_user():
#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/types.h>
int main(int argc, char **argv)
{
unsigned long page_size = sysconf(_SC_PAGESIZE);
char *p = malloc(3 * page_size);
char *p_aligned;
/* initialize memory region. If not initialized, write syscall below will correctly return EFAULT. */
if (1)
memset(p, 'X', 3 * page_size);
p_aligned = (char *) ((((uintptr_t) p) + (2*page_size - 1)) & ~(page_size - 1));
/* Drop PROT_READ protection. Kernel and userspace should fault when accessing that memory region */
mprotect(p_aligned, page_size, PROT_NONE);
/* the following write() should return EFAULT, since PROT_READ was dropped by previous mprotect() */
int ret = write(2, p_aligned, 1);
if (!ret || errno != EFAULT)
printf("\n FAILURE: write() did not returned expected EFAULT value\n");
return 0;
}
Because of the way _PAGE_READ is handled, kernel code never generates
a read access fault when it access a page as the kernel privilege level
is always less than PL1 in the PTE.
This patch reworks the comments in the make_insert_tlb macro to try
to make this clearer.
Signed-off-by: John David Anglin <dave.anglin(a)bell.net>
Signed-off-by: Helge Deller <deller(a)gmx.de>
Cc: stable(a)vger.kernel.org # v5.12+
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index ea57bcc21dc5..f4bf61a34701 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -499,6 +499,12 @@
* this happens is quite subtle, read below */
.macro make_insert_tlb spc,pte,prot,tmp
space_to_prot \spc \prot /* create prot id from space */
+
+#if _PAGE_SPECIAL_BIT == _PAGE_DMB_BIT
+ /* need to drop DMB bit, as it's used as SPECIAL flag */
+ depi 0,_PAGE_SPECIAL_BIT,1,\pte
+#endif
+
/* The following is the real subtlety. This is depositing
* T <-> _PAGE_REFTRAP
* D <-> _PAGE_DIRTY
@@ -511,17 +517,18 @@
* Finally, _PAGE_READ goes in the top bit of PL1 (so we
* trigger an access rights trap in user space if the user
* tries to read an unreadable page */
-#if _PAGE_SPECIAL_BIT == _PAGE_DMB_BIT
- /* need to drop DMB bit, as it's used as SPECIAL flag */
- depi 0,_PAGE_SPECIAL_BIT,1,\pte
-#endif
depd \pte,8,7,\prot
/* PAGE_USER indicates the page can be read with user privileges,
* so deposit X1|11 to PL1|PL2 (remember the upper bit of PL1
- * contains _PAGE_READ) */
+ * contains _PAGE_READ). While the kernel can't directly write
+ * user pages which have _PAGE_WRITE zero, it can read pages
+ * which have _PAGE_READ zero (PL <= PL1). Thus, the kernel
+ * exception fault handler doesn't trigger when reading pages
+ * that aren't user read accessible */
extrd,u,*= \pte,_PAGE_USER_BIT+32,1,%r0
depdi 7,11,3,\prot
+
/* If we're a gateway page, drop PL2 back to zero for promotion
* to kernel privilege (so we can execute the page as kernel).
* Any privilege promotion page always denys read and write */
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 f92a5e36b0c45cd12ac0d1bc44680c0dfae34543
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025082119-refining-upstream-528c@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f92a5e36b0c45cd12ac0d1bc44680c0dfae34543 Mon Sep 17 00:00:00 2001
From: John David Anglin <dave.anglin(a)bell.net>
Date: Mon, 21 Jul 2025 16:13:13 -0400
Subject: [PATCH] parisc: Try to fixup kernel exception in bad_area_nosemaphore
path of do_page_fault()
Signed-off-by: John David Anglin <dave.anglin(a)bell.net>
Signed-off-by: Helge Deller <deller(a)gmx.de>
Cc: stable(a)vger.kernel.org # v5.12+
diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index c39de84e98b0..f1785640b049 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -363,6 +363,10 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
mmap_read_unlock(mm);
bad_area_nosemaphore:
+ if (!user_mode(regs) && fixup_exception(regs)) {
+ return;
+ }
+
if (user_mode(regs)) {
int signo, si_code;