The fbdev sysfs attributes are registered after sending the uevent for
the device creation, leaving a race window where e.g. udev rules may
not be able to access the sysfs attributes because the registration is
not done yet.
Fix this by switching to device_create_with_groups(). This also results in
a nice cleanup. After switching to device_create_with_groups() all that
is left of fb_init_device() is setting the drvdata and that can be passed
to device_create[_with_groups]() too. After which fb_init_device() can
be completely removed.
Dropping fb_init_device() + fb_cleanup_device() in turn allows removing
fb_info.class_flag as they were the only user of this field.
Fixes: 5fc830d6aca1 ("fbdev: Register sysfs groups through device_add_group")
Cc: stable(a)vger.kernel.org
Cc: Shixiong Ou <oushixiong(a)kylinos.cn>
Signed-off-by: Hans de Goede <johannes.goede(a)oss.qualcomm.com>
---
Note the fixes tag is technically wrong. This race has existed forever.
The commit I picked for the fixes tag is a dependency of this change not
the commit introducing the race. I don't believe that backporting this
back any further is useful which is why I went with this commit.
---
drivers/video/fbdev/core/fbsysfs.c | 36 +++---------------------------
include/linux/fb.h | 1 -
2 files changed, 3 insertions(+), 34 deletions(-)
diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c
index b8344c40073b..baa2bae0fb5b 100644
--- a/drivers/video/fbdev/core/fbsysfs.c
+++ b/drivers/video/fbdev/core/fbsysfs.c
@@ -12,8 +12,6 @@
#include "fb_internal.h"
-#define FB_SYSFS_FLAG_ATTR 1
-
static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var)
{
int err;
@@ -451,33 +449,7 @@ static struct attribute *fb_device_attrs[] = {
NULL,
};
-static const struct attribute_group fb_device_attr_group = {
- .attrs = fb_device_attrs,
-};
-
-static int fb_init_device(struct fb_info *fb_info)
-{
- int ret;
-
- dev_set_drvdata(fb_info->dev, fb_info);
-
- fb_info->class_flag |= FB_SYSFS_FLAG_ATTR;
-
- ret = device_add_group(fb_info->dev, &fb_device_attr_group);
- if (ret)
- fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
-
- return 0;
-}
-
-static void fb_cleanup_device(struct fb_info *fb_info)
-{
- if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) {
- device_remove_group(fb_info->dev, &fb_device_attr_group);
-
- fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR;
- }
-}
+ATTRIBUTE_GROUPS(fb_device);
int fb_device_create(struct fb_info *fb_info)
{
@@ -485,14 +457,13 @@ int fb_device_create(struct fb_info *fb_info)
dev_t devt = MKDEV(FB_MAJOR, node);
int ret;
- fb_info->dev = device_create(fb_class, fb_info->device, devt, NULL, "fb%d", node);
+ fb_info->dev = device_create_with_groups(fb_class, fb_info->device, devt, fb_info,
+ fb_device_groups, "fb%d", node);
if (IS_ERR(fb_info->dev)) {
/* Not fatal */
ret = PTR_ERR(fb_info->dev);
pr_warn("Unable to create device for framebuffer %d; error %d\n", node, ret);
fb_info->dev = NULL;
- } else {
- fb_init_device(fb_info);
}
return 0;
@@ -505,7 +476,6 @@ void fb_device_destroy(struct fb_info *fb_info)
if (!fb_info->dev)
return;
- fb_cleanup_device(fb_info);
device_destroy(fb_class, devt);
fb_info->dev = NULL;
}
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 05cc251035da..c3302d513546 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -497,7 +497,6 @@ struct fb_info {
#if defined(CONFIG_FB_DEVICE)
struct device *dev; /* This is this fb device */
#endif
- int class_flag; /* private sysfs flags */
#ifdef CONFIG_FB_TILEBLITTING
struct fb_tile_ops *tileops; /* Tile Blitting */
#endif
--
2.52.0
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erofs readahead could fail with ENOMEM under the memory pressure because
it tries to alloc_page with GFP_NOWAIT | GFP_NORETRY, while GFP_KERNEL
for a regular read. And if readahead fails (with non-uptodate folios),
the original request will then fall back to synchronous read, and
`.read_folio()` should return appropriate errnos.
However, in scenarios where readahead and read operations compete,
read operation could return an unintended EIO because of an incorrect
error propagation.
To resolve this, this patch modifies the behavior so that, when the
PCL is for read(which means pcl.besteffort is true), it attempts actual
decompression instead of propagating the privios error except initial EIO.
- Page size: 4K
- The original size of FileA: 16K
- Compress-ratio per PCL: 50% (Uncompressed 8K -> Compressed 4K)
[page0, page1] [page2, page3]
[PCL0]---------[PCL1]
- functions declaration:
. pread(fd, buf, count, offset)
. readahead(fd, offset, count)
- Thread A tries to read the last 4K
- Thread B tries to do readahead 8K from 4K
- RA, besteffort == false
- R, besteffort == true
<process A> <process B>
pread(FileA, buf, 4K, 12K)
do readahead(page3) // failed with ENOMEM
wait_lock(page3)
if (!uptodate(page3))
goto do_read
readahead(FileA, 4K, 8K)
// Here create PCL-chain like below:
// [null, page1] [page2, null]
// [PCL0:RA]-----[PCL1:RA]
...
do read(page3) // found [PCL1:RA] and add page3 into it,
// and then, change PCL1 from RA to R
...
// Now, PCL-chain is as below:
// [null, page1] [page2, page3]
// [PCL0:RA]-----[PCL1:R]
// try to decompress PCL-chain...
z_erofs_decompress_queue
err = 0;
// failed with ENOMEM, so page 1
// only for RA will not be uptodated.
// it's okay.
err = decompress([PCL0:RA], err)
// However, ENOMEM propagated to next
// PCL, even though PCL is not only
// for RA but also for R. As a result,
// it just failed with ENOMEM without
// trying any decompression, so page2
// and page3 will not be uptodated.
** BUG HERE ** --> err = decompress([PCL1:R], err)
return err as ENOMEM
...
wait_lock(page3)
if (!uptodate(page3))
return EIO <-- Return an unexpected EIO!
...
Fixes: 2349d2fa02db ("erofs: sunset unneeded NOFAILs")
Cc: stable(a)vger.kernel.org
Reviewed-by: Jaewook Kim <jw5454.kim(a)samsung.com>
Reviewed-by: Sungjong Seo <sj1557.seo(a)samsung.com>
Signed-off-by: Junbeom Yeom <junbeom.yeom(a)samsung.com>
---
v2:
- If disk I/Os are successful, handle to decompress each pcluster.
fs/erofs/zdata.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 27b1f44d10ce..70e1597dec8a 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1262,7 +1262,7 @@ static int z_erofs_parse_in_bvecs(struct z_erofs_backend *be, bool *overlapped)
return err;
}
-static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, int err)
+static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, bool eio)
{
struct erofs_sb_info *const sbi = EROFS_SB(be->sb);
struct z_erofs_pcluster *pcl = be->pcl;
@@ -1270,7 +1270,7 @@ static int z_erofs_decompress_pcluster(struct z_erofs_backend *be, int err)
const struct z_erofs_decompressor *alg =
z_erofs_decomp[pcl->algorithmformat];
bool try_free = true;
- int i, j, jtop, err2;
+ int i, j, jtop, err2, err = eio ? -EIO : 0;
struct page *page;
bool overlapped;
const char *reason;
@@ -1413,12 +1413,12 @@ static int z_erofs_decompress_queue(const struct z_erofs_decompressqueue *io,
.pcl = io->head,
};
struct z_erofs_pcluster *next;
- int err = io->eio ? -EIO : 0;
+ int err = 0;
for (; be.pcl != Z_EROFS_PCLUSTER_TAIL; be.pcl = next) {
DBG_BUGON(!be.pcl);
next = READ_ONCE(be.pcl->next);
- err = z_erofs_decompress_pcluster(&be, err) ?: err;
+ err = z_erofs_decompress_pcluster(&be, io->eio) ?: err;
}
return err;
}
--
2.34.1
Since commit c6e126de43e7 ("of: Keep track of populated platform
devices") child devices will not be created by of_platform_populate()
if the devices had previously been deregistered individually so that the
OF_POPULATED flag is still set in the corresponding OF nodes.
Switch to using of_platform_depopulate() instead of open coding so that
the child devices are created if the driver is rebound.
Fixes: c6e126de43e7 ("of: Keep track of populated platform devices")
Cc: stable(a)vger.kernel.org # 3.16
Signed-off-by: Johan Hovold <johan(a)kernel.org>
---
drivers/mfd/qcom-pm8xxx.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/drivers/mfd/qcom-pm8xxx.c b/drivers/mfd/qcom-pm8xxx.c
index 1149f7102a36..0cf374c015ce 100644
--- a/drivers/mfd/qcom-pm8xxx.c
+++ b/drivers/mfd/qcom-pm8xxx.c
@@ -577,17 +577,11 @@ static int pm8xxx_probe(struct platform_device *pdev)
return rc;
}
-static int pm8xxx_remove_child(struct device *dev, void *unused)
-{
- platform_device_unregister(to_platform_device(dev));
- return 0;
-}
-
static void pm8xxx_remove(struct platform_device *pdev)
{
struct pm_irq_chip *chip = platform_get_drvdata(pdev);
- device_for_each_child(&pdev->dev, NULL, pm8xxx_remove_child);
+ of_platform_depopulate(&pdev->dev);
irq_domain_remove(chip->irqdomain);
}
--
2.51.2
The patch titled
Subject: AMDGPU: fix failure with periodic signal
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
fix-amdgpu-failure-with-periodic-signal.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Mikulas Patocka <mpatocka(a)redhat.com>
Subject: AMDGPU: fix failure with periodic signal
Date: Fri, 7 Nov 2025 18:48:01 +0100 (CET)
If a process sets up a timer that periodically sends a signal in short
intervals and if it uses OpenCL on AMDGPU at the same time, we get random
errors. Sometimes, probing the OpenCL device fails (strace shows that
open("/dev/kfd") failed with -EINTR). Sometimes we get the message
"amdgpu: init_user_pages: Failed to register MMU notifier: -4" in the
syslog.
The bug can be reproduced with this program:
http://www.jikos.cz/~mikulas/testcases/opencl/opencl-bug-small.c
The root cause for these failures is in the function mm_take_all_locks.
This function fails with -EINTR if there is pending signal. The -EINTR is
propagated up the call stack to userspace and userspace fails if it gets
this error.
There is the following call chain: kfd_open -> kfd_create_process ->
create_process -> mmu_notifier_get -> mmu_notifier_get_locked ->
__mmu_notifier_register -> mm_take_all_locks -> "return -EINTR"
If the failure happens in init_user_pages, there is the following call
chain: init_user_pages -> amdgpu_hmm_register ->
mmu_interval_notifier_insert -> mmu_notifier_register ->
__mmu_notifier_register -> mm_take_all_locks -> "return -EINTR"
In order to fix these failures, this commit changes
signal_pending(current) to fatal_signal_pending(current) in
mm_take_all_locks, so that it is interrupted only if the signal is
actually killing the process.
Also, this commit skips pr_err in init_user_pages if the process is being
killed - in this situation, there was no error and so we don't want to
report it in the syslog.
I'm submitting this patch for the stable kernels, because this bug may
cause random failures in any OpenCL code.
Link: https://lkml.kernel.org/r/6f16b618-26fc-3031-abe8-65c2090262e7@redhat.com
Signed-off-by: Mikulas Patocka <mpatocka(a)redhat.com>
Cc: Alexander Deucher <alexander.deucher(a)amd.com>
Cc: Christan K��nig <christian.koenig(a)amd.com>
Cc: David Hildenbrand <david(a)redhat.com>
Cc: "Liam R. Howlett" <Liam.Howlett(a)oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com>
Cc: Vlastimil Babka <vbabka(a)suse.cz>
Cc: Jann Horn <jannh(a)google.com>
Cc: Pedro Falcato <pfalcato(a)suse.de>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 9 +++++++--
mm/vma.c | 8 ++++----
2 files changed, 11 insertions(+), 6 deletions(-)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c~fix-amdgpu-failure-with-periodic-signal
+++ a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1070,8 +1070,13 @@ static int init_user_pages(struct kgd_me
ret = amdgpu_hmm_register(bo, user_addr);
if (ret) {
- pr_err("%s: Failed to register MMU notifier: %d\n",
- __func__, ret);
+ /*
+ * If we got EINTR because the process was killed, don't report
+ * it, because no error happened.
+ */
+ if (!(fatal_signal_pending(current) && ret == -EINTR))
+ pr_err("%s: Failed to register MMU notifier: %d\n",
+ __func__, ret);
goto out;
}
--- a/mm/vma.c~fix-amdgpu-failure-with-periodic-signal
+++ a/mm/vma.c
@@ -2166,14 +2166,14 @@ int mm_take_all_locks(struct mm_struct *
* is reached.
*/
for_each_vma(vmi, vma) {
- if (signal_pending(current))
+ if (fatal_signal_pending(current))
goto out_unlock;
vma_start_write(vma);
}
vma_iter_init(&vmi, mm, 0);
for_each_vma(vmi, vma) {
- if (signal_pending(current))
+ if (fatal_signal_pending(current))
goto out_unlock;
if (vma->vm_file && vma->vm_file->f_mapping &&
is_vm_hugetlb_page(vma))
@@ -2182,7 +2182,7 @@ int mm_take_all_locks(struct mm_struct *
vma_iter_init(&vmi, mm, 0);
for_each_vma(vmi, vma) {
- if (signal_pending(current))
+ if (fatal_signal_pending(current))
goto out_unlock;
if (vma->vm_file && vma->vm_file->f_mapping &&
!is_vm_hugetlb_page(vma))
@@ -2191,7 +2191,7 @@ int mm_take_all_locks(struct mm_struct *
vma_iter_init(&vmi, mm, 0);
for_each_vma(vmi, vma) {
- if (signal_pending(current))
+ if (fatal_signal_pending(current))
goto out_unlock;
if (vma->anon_vma)
list_for_each_entry(avc, &vma->anon_vma_chain, same_vma)
_
Patches currently in -mm which might be from mpatocka(a)redhat.com are
fix-amdgpu-failure-with-periodic-signal.patch
The patch titled
Subject: mm/page_owner: fix memory leak in page_owner_stack_fops->release()
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-page_owner-fix-memory-leak-in-page_owner_stack_fops-release.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Ran Xiaokai <ran.xiaokai(a)zte.com.cn>
Subject: mm/page_owner: fix memory leak in page_owner_stack_fops->release()
Date: Fri, 19 Dec 2025 07:42:32 +0000
The page_owner_stack_fops->open() callback invokes seq_open_private(),
therefore its corresponding ->release() callback must call
seq_release_private(). Otherwise it will cause a memory leak of struct
stack_print_ctx.
Link: https://lkml.kernel.org/r/20251219074232.136482-1-ranxiaokai627@163.com
Fixes: 765973a098037 ("mm,page_owner: display all stacks and their count")
Signed-off-by: Ran Xiaokai <ran.xiaokai(a)zte.com.cn>
Acked-by: Michal Hocko <mhocko(a)suse.com>
Acked-by: Vlastimil Babka <vbabka(a)suse.cz>
Cc: Andrey Konovalov <andreyknvl(a)gmail.com>
Cc: Brendan Jackman <jackmanb(a)google.com>
Cc: Johannes Weiner <hannes(a)cmpxchg.org>
Cc: Marco Elver <elver(a)google.com>
Cc: Suren Baghdasaryan <surenb(a)google.com>
Cc: Zi Yan <ziy(a)nvidia.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/page_owner.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/page_owner.c~mm-page_owner-fix-memory-leak-in-page_owner_stack_fops-release
+++ a/mm/page_owner.c
@@ -952,7 +952,7 @@ static const struct file_operations page
.open = page_owner_stack_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = seq_release,
+ .release = seq_release_private,
};
static int page_owner_threshold_get(void *data, u64 *val)
_
Patches currently in -mm which might be from ran.xiaokai(a)zte.com.cn are
mm-page_owner-fix-memory-leak-in-page_owner_stack_fops-release.patch
The patch titled
Subject: mm/memory-failure: fix missing ->mf_stats count in hugetlb poison
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-memory-failure-fix-missing-mf_stats-count-in-hugetlb-poison.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Jane Chu <jane.chu(a)oracle.com>
Subject: mm/memory-failure: fix missing ->mf_stats count in hugetlb poison
Date: Fri, 19 Dec 2025 12:15:58 -0700
When a newly poisoned subpage ends up in an already poisoned hugetlb
folio, 'num_poisoned_pages' is incremented, but the per node ->mf_stats is
not. Fix the inconsistency by designating action_result() to update them
both.
While at it, define __get_huge_page_for_hwpoison() return values in terms
of symbol names for better readibility. Also rename
folio_set_hugetlb_hwpoison() to hugetlb_update_hwpoison() since the
function does more than the conventional bit setting and the fact three
possible return values are expected.
Link: https://lkml.kernel.org/r/20251219191559.2962716-1-jane.chu@oracle.com
Fixes: 18f41fa616ee4 ("mm: memory-failure: bump memory failure stats to pglist_data")
Signed-off-by: Jane Chu <jane.chu(a)oracle.com>
Cc: "David Hildenbrand (Red Hat)" <david(a)kernel.org>
Cc: David Rientjes <rientjes(a)google.com>
Cc: Jiaqi Yan <jiaqiyan(a)google.com>
Cc: Liam Howlett <liam.howlett(a)oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com>
Cc: Miaohe Lin <linmiaohe(a)huawei.com>
Cc: Michal Hocko <mhocko(a)suse.com>
Cc: Mike Rapoport <rppt(a)kernel.org>
Cc: Muchun Song <muchun.song(a)linux.dev>
Cc: Oscar Salvador <osalvador(a)suse.de>
Cc: Suren Baghdasaryan <surenb(a)google.com>
Cc: William Roche <william.roche(a)oracle.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/memory-failure.c | 56 ++++++++++++++++++++++++------------------
1 file changed, 33 insertions(+), 23 deletions(-)
--- a/mm/memory-failure.c~mm-memory-failure-fix-missing-mf_stats-count-in-hugetlb-poison
+++ a/mm/memory-failure.c
@@ -1883,12 +1883,18 @@ static unsigned long __folio_free_raw_hw
return count;
}
-static int folio_set_hugetlb_hwpoison(struct folio *folio, struct page *page)
+#define MF_HUGETLB_ALREADY_POISONED 3 /* already poisoned */
+#define MF_HUGETLB_ACC_EXISTING_POISON 4 /* accessed existing poisoned page */
+/*
+ * Set hugetlb folio as hwpoisoned, update folio private raw hwpoison list
+ * to keep track of the poisoned pages.
+ */
+static int hugetlb_update_hwpoison(struct folio *folio, struct page *page)
{
struct llist_head *head;
struct raw_hwp_page *raw_hwp;
struct raw_hwp_page *p;
- int ret = folio_test_set_hwpoison(folio) ? -EHWPOISON : 0;
+ int ret = folio_test_set_hwpoison(folio) ? MF_HUGETLB_ALREADY_POISONED : 0;
/*
* Once the hwpoison hugepage has lost reliable raw error info,
@@ -1896,20 +1902,18 @@ static int folio_set_hugetlb_hwpoison(st
* so skip to add additional raw error info.
*/
if (folio_test_hugetlb_raw_hwp_unreliable(folio))
- return -EHWPOISON;
+ return MF_HUGETLB_ALREADY_POISONED;
+
head = raw_hwp_list_head(folio);
llist_for_each_entry(p, head->first, node) {
if (p->page == page)
- return -EHWPOISON;
+ return MF_HUGETLB_ACC_EXISTING_POISON;
}
raw_hwp = kmalloc(sizeof(struct raw_hwp_page), GFP_ATOMIC);
if (raw_hwp) {
raw_hwp->page = page;
llist_add(&raw_hwp->node, head);
- /* the first error event will be counted in action_result(). */
- if (ret)
- num_poisoned_pages_inc(page_to_pfn(page));
} else {
/*
* Failed to save raw error info. We no longer trace all
@@ -1955,32 +1959,30 @@ void folio_clear_hugetlb_hwpoison(struct
folio_free_raw_hwp(folio, true);
}
+#define MF_HUGETLB_FREED 0 /* freed hugepage */
+#define MF_HUGETLB_IN_USED 1 /* in-use hugepage */
+#define MF_NOT_HUGETLB 2 /* not a hugepage */
+
/*
* Called from hugetlb code with hugetlb_lock held.
- *
- * Return values:
- * 0 - free hugepage
- * 1 - in-use hugepage
- * 2 - not a hugepage
- * -EBUSY - the hugepage is busy (try to retry)
- * -EHWPOISON - the hugepage is already hwpoisoned
*/
int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
bool *migratable_cleared)
{
struct page *page = pfn_to_page(pfn);
struct folio *folio = page_folio(page);
- int ret = 2; /* fallback to normal page handling */
+ int ret = MF_NOT_HUGETLB;
bool count_increased = false;
+ int rc;
if (!folio_test_hugetlb(folio))
goto out;
if (flags & MF_COUNT_INCREASED) {
- ret = 1;
+ ret = MF_HUGETLB_IN_USED;
count_increased = true;
} else if (folio_test_hugetlb_freed(folio)) {
- ret = 0;
+ ret = MF_HUGETLB_FREED;
} else if (folio_test_hugetlb_migratable(folio)) {
ret = folio_try_get(folio);
if (ret)
@@ -1991,8 +1993,9 @@ int __get_huge_page_for_hwpoison(unsigne
goto out;
}
- if (folio_set_hugetlb_hwpoison(folio, page)) {
- ret = -EHWPOISON;
+ rc = hugetlb_update_hwpoison(folio, page);
+ if (rc >= MF_HUGETLB_ALREADY_POISONED) {
+ ret = rc;
goto out;
}
@@ -2029,22 +2032,29 @@ static int try_memory_failure_hugetlb(un
*hugetlb = 1;
retry:
res = get_huge_page_for_hwpoison(pfn, flags, &migratable_cleared);
- if (res == 2) { /* fallback to normal page handling */
+ switch (res) {
+ case MF_NOT_HUGETLB: /* fallback to normal page handling */
*hugetlb = 0;
return 0;
- } else if (res == -EHWPOISON) {
+ case MF_HUGETLB_ALREADY_POISONED:
+ case MF_HUGETLB_ACC_EXISTING_POISON:
if (flags & MF_ACTION_REQUIRED) {
folio = page_folio(p);
res = kill_accessing_process(current, folio_pfn(folio), flags);
}
- action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED);
+ if (res == MF_HUGETLB_ALREADY_POISONED)
+ action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED);
+ else
+ action_result(pfn, MF_MSG_HUGE, MF_FAILED);
return res;
- } else if (res == -EBUSY) {
+ case -EBUSY:
if (!(flags & MF_NO_RETRY)) {
flags |= MF_NO_RETRY;
goto retry;
}
return action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED);
+ default:
+ break;
}
folio = page_folio(p);
_
Patches currently in -mm which might be from jane.chu(a)oracle.com are
mm-memory-failure-fix-missing-mf_stats-count-in-hugetlb-poison.patch
From: Ionut Nechita <ionut.nechita(a)windriver.com>
This series addresses two critical performance regressions in the block
layer multiqueue (blk-mq) subsystem when running on PREEMPT_RT kernels.
On RT kernels, regular spinlocks are converted to sleeping rt_mutex locks,
which can cause severe performance degradation in the I/O hot path. This
series converts two problematic locking patterns to prevent IRQ threads
from sleeping during I/O operations.
Testing on MegaRAID 12GSAS controller with 8 MSI-X vectors shows:
- v6.6.52-rt (before regression): 640 MB/s sequential read
- v6.6.64-rt (regression introduced): 153 MB/s (-76% regression)
- v6.6.68-rt with queue_lock fix only: 640 MB/s (performance restored)
- v6.6.69-rt with both fixes: expected similar or better performance
The first patch replaces queue_lock with memory barriers in the I/O
completion hot path, eliminating the contention that caused IRQ threads
to sleep. The second patch converts the global blk_mq_cpuhp_lock from
mutex to raw_spinlock to prevent sleeping during CPU hotplug operations.
Both conversions are safe because the protected code paths only perform
fast, non-blocking operations (memory barriers, list/hlist manipulation,
flag checks).
Ionut Nechita (2):
block/blk-mq: fix RT kernel regression with queue_lock in hot path
block/blk-mq: convert blk_mq_cpuhp_lock to raw_spinlock for RT
block/blk-mq.c | 33 +++++++++++++++------------------
1 file changed, 15 insertions(+), 18 deletions(-)
--
2.52.0
When of_find_net_device_by_node() successfully acquires a reference to
a network device but the subsequent call to dsa_port_parse_cpu()
fails, dsa_port_parse_of() returns without releasing the reference
count on the network device.
of_find_net_device_by_node() increments the reference count of the
returned structure, which should be balanced with a corresponding
put_device() when the reference is no longer needed.
Found by code review.
Cc: stable(a)vger.kernel.org
Fixes: deff710703d8 ("net: dsa: Allow default tag protocol to be overridden from DT")
Signed-off-by: Ma Ke <make24(a)iscas.ac.cn>
---
Changes in v2:
- simplified the patch as suggestions;
- modified the Fixes tag as suggestions.
---
net/dsa/dsa.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index a20efabe778f..31b409a47491 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -1247,6 +1247,7 @@ static int dsa_port_parse_of(struct dsa_port *dp, struct device_node *dn)
struct device_node *ethernet = of_parse_phandle(dn, "ethernet", 0);
const char *name = of_get_property(dn, "label", NULL);
bool link = of_property_read_bool(dn, "link");
+ int err = 0;
dp->dn = dn;
@@ -1260,7 +1261,11 @@ static int dsa_port_parse_of(struct dsa_port *dp, struct device_node *dn)
return -EPROBE_DEFER;
user_protocol = of_get_property(dn, "dsa-tag-protocol", NULL);
- return dsa_port_parse_cpu(dp, conduit, user_protocol);
+ err = dsa_port_parse_cpu(dp, conduit, user_protocol);
+ if (err)
+ put_device(conduit);
+
+ return err;
}
if (link)
--
2.17.1
__arm_lpae_unmap() returns size_t but was returning -ENOENT (negative
error code) when encountering an unmapped PTE. Since size_t is unsigned,
-ENOENT (typically -2) becomes a huge positive value (0xFFFFFFFFFFFFFFFE
on 64-bit systems).
This corrupted value propagates through the call chain:
__arm_lpae_unmap() returns -ENOENT as size_t
-> arm_lpae_unmap_pages() returns it
-> __iommu_unmap() adds it to iova address
-> iommu_pgsize() triggers BUG_ON due to corrupted iova
This can cause IOVA address overflow in __iommu_unmap() loop and
trigger BUG_ON in iommu_pgsize() from invalid address alignment.
Fix by returning 0 instead of -ENOENT. The WARN_ON already signals
the error condition, and returning 0 (meaning "nothing unmapped")
is the correct semantic for size_t return type. This matches the
behavior of other io-pgtable implementations (io-pgtable-arm-v7s,
io-pgtable-dart) which return 0 on error conditions.
Fixes: 3318f7b5cefb ("iommu/io-pgtable-arm: Add quirk to quiet WARN_ON()")
Cc: stable(a)vger.kernel.org
Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux(a)gmail.com>
---
drivers/iommu/io-pgtable-arm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index e6626004b323..05d63fe92e43 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -637,7 +637,7 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
pte = READ_ONCE(*ptep);
if (!pte) {
WARN_ON(!(data->iop.cfg.quirks & IO_PGTABLE_QUIRK_NO_WARN));
- return -ENOENT;
+ return 0;
}
/* If the size matches this level, we're in the right place */
--
2.40.0
From: Alex Deucher <alexander.deucher(a)amd.com>
commit eb296c09805ee37dd4ea520a7fb3ec157c31090f upstream.
SI hardware doesn't support pasids, user mode queues, or
KIQ/MES so there is no need for this. Doing so results in
a segfault as these callbacks are non-existent for SI.
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4744
Fixes: b4a7f4e7ad2b ("drm/amdgpu: attach tlb fence to the PTs update")
Reviewed-by: Timur Kristóf <timur.kristof(a)gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher(a)amd.com>
(cherry picked from commit 820b3d376e8a102c6aeab737ec6edebbbb710e04)
Signed-off-by: Hans de Goede <johannes.goede(a)oss.qualcomm.com>
---
Changes in v2 stable submission:
- Correct the Fixes: tag hash which is wrong in the original upstream
commit eb296c09805e ("drm/amdgpu: don't attach the tlb fence for SI")
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 676e24fb8864..cdcafde3c71a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1066,7 +1066,9 @@ amdgpu_vm_tlb_flush(struct amdgpu_vm_update_params *params,
}
/* Prepare a TLB flush fence to be attached to PTs */
- if (!params->unlocked) {
+ if (!params->unlocked &&
+ /* SI doesn't support pasid or KIQ/MES */
+ params->adev->family > AMDGPU_FAMILY_SI) {
amdgpu_vm_tlb_fence_create(params->adev, vm, fence);
/* Makes sure no PD/PT is freed before the flush */
--
2.52.0
From: Ionut Nechita <ionut.nechita(a)windriver.com>
Commit 679b1874eba7 ("block: fix ordering between checking
QUEUE_FLAG_QUIESCED request adding") introduced queue_lock acquisition
in blk_mq_run_hw_queue() to synchronize QUEUE_FLAG_QUIESCED checks.
On RT kernels (CONFIG_PREEMPT_RT), regular spinlocks are converted to
rt_mutex (sleeping locks). When multiple MSI-X IRQ threads process I/O
completions concurrently, they contend on queue_lock in the hot path,
causing all IRQ threads to enter D (uninterruptible sleep) state. This
serializes interrupt processing completely.
Test case (MegaRAID 12GSAS with 8 MSI-X vectors on RT kernel):
- Good (v6.6.52-rt): 640 MB/s sequential read
- Bad (v6.6.64-rt): 153 MB/s sequential read (-76% regression)
- 6-8 out of 8 MSI-X IRQ threads stuck in D-state waiting on queue_lock
The original commit message mentioned memory barriers as an alternative
approach. Use full memory barriers (smp_mb) instead of queue_lock to
provide the same ordering guarantees without sleeping in RT kernel.
Memory barriers ensure proper synchronization:
- CPU0 either sees QUEUE_FLAG_QUIESCED cleared, OR
- CPU1 sees dispatch list/sw queue bitmap updates
This maintains correctness while avoiding lock contention that causes
RT kernel IRQ threads to sleep in the I/O completion path.
Fixes: 679b1874eba7 ("block: fix ordering between checking QUEUE_FLAG_QUIESCED request adding")
Cc: stable(a)vger.kernel.org
Signed-off-by: Ionut Nechita <ionut.nechita(a)windriver.com>
---
block/blk-mq.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 5da948b07058..5fb8da4958d0 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2292,22 +2292,19 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING);
+ /*
+ * First lockless check to avoid unnecessary overhead.
+ * Memory barrier below synchronizes with blk_mq_unquiesce_queue().
+ */
need_run = blk_mq_hw_queue_need_run(hctx);
if (!need_run) {
- unsigned long flags;
-
- /*
- * Synchronize with blk_mq_unquiesce_queue(), because we check
- * if hw queue is quiesced locklessly above, we need the use
- * ->queue_lock to make sure we see the up-to-date status to
- * not miss rerunning the hw queue.
- */
- spin_lock_irqsave(&hctx->queue->queue_lock, flags);
+ /* Synchronize with blk_mq_unquiesce_queue() */
+ smp_mb();
need_run = blk_mq_hw_queue_need_run(hctx);
- spin_unlock_irqrestore(&hctx->queue->queue_lock, flags);
-
if (!need_run)
return;
+ /* Ensure dispatch list/sw queue updates visible before execution */
+ smp_mb();
}
if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) {
--
2.52.0
From: Ilya Maximets <i.maximets(a)ovn.org>
[ Upstream commit 5ace7ef87f059d68b5f50837ef3e8a1a4870c36e ]
The push_nsh() action structure looks like this:
OVS_ACTION_ATTR_PUSH_NSH(OVS_KEY_ATTR_NSH(OVS_NSH_KEY_ATTR_BASE,...))
The outermost OVS_ACTION_ATTR_PUSH_NSH attribute is OK'ed by the
nla_for_each_nested() inside __ovs_nla_copy_actions(). The innermost
OVS_NSH_KEY_ATTR_BASE/MD1/MD2 are OK'ed by the nla_for_each_nested()
inside nsh_key_put_from_nlattr(). But nothing checks if the attribute
in the middle is OK. We don't even check that this attribute is the
OVS_KEY_ATTR_NSH. We just do a double unwrap with a pair of nla_data()
calls - first time directly while calling validate_push_nsh() and the
second time as part of the nla_for_each_nested() macro, which isn't
safe, potentially causing invalid memory access if the size of this
attribute is incorrect. The failure may not be noticed during
validation due to larger netlink buffer, but cause trouble later during
action execution where the buffer is allocated exactly to the size:
BUG: KASAN: slab-out-of-bounds in nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch]
Read of size 184 at addr ffff88816459a634 by task a.out/22624
CPU: 8 UID: 0 PID: 22624 6.18.0-rc7+ #115 PREEMPT(voluntary)
Call Trace:
<TASK>
dump_stack_lvl+0x51/0x70
print_address_description.constprop.0+0x2c/0x390
kasan_report+0xdd/0x110
kasan_check_range+0x35/0x1b0
__asan_memcpy+0x20/0x60
nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch]
push_nsh+0x82/0x120 [openvswitch]
do_execute_actions+0x1405/0x2840 [openvswitch]
ovs_execute_actions+0xd5/0x3b0 [openvswitch]
ovs_packet_cmd_execute+0x949/0xdb0 [openvswitch]
genl_family_rcv_msg_doit+0x1d6/0x2b0
genl_family_rcv_msg+0x336/0x580
genl_rcv_msg+0x9f/0x130
netlink_rcv_skb+0x11f/0x370
genl_rcv+0x24/0x40
netlink_unicast+0x73e/0xaa0
netlink_sendmsg+0x744/0xbf0
__sys_sendto+0x3d6/0x450
do_syscall_64+0x79/0x2c0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
</TASK>
Let's add some checks that the attribute is properly sized and it's
the only one attribute inside the action. Technically, there is no
real reason for OVS_KEY_ATTR_NSH to be there, as we know that we're
pushing an NSH header already, it just creates extra nesting, but
that's how uAPI works today. So, keeping as it is.
Fixes: b2d0f5d5dc53 ("openvswitch: enable NSH support")
Reported-by: Junvy Yang <zhuque(a)tencent.com>
Signed-off-by: Ilya Maximets <i.maximets(a)ovn.org>
Acked-by: Eelco Chaudron <echaudro(a)redhat.com>
Reviewed-by: Aaron Conole <aconole(a)redhat.com>
Link: https://patch.msgid.link/20251204105334.900379-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
(cherry picked from commit 5ace7ef87f059d68b5f50837ef3e8a1a4870c36e)
Signed-off-by: Adrian Yip <adrian.ytw(a)gmail.com>
---
net/openvswitch/flow_netlink.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index 1cb4f97335d8..2d536901309e 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -2802,13 +2802,20 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
return err;
}
-static bool validate_push_nsh(const struct nlattr *attr, bool log)
+static bool validate_push_nsh(const struct nlattr *a, bool log)
{
+ struct nlattr *nsh_key = nla_data(a);
struct sw_flow_match match;
struct sw_flow_key key;
+ /* There must be one and only one NSH header. */
+ if (!nla_ok(nsh_key, nla_len(a)) ||
+ nla_total_size(nla_len(nsh_key)) != nla_len(a) ||
+ nla_type(nsh_key) != OVS_KEY_ATTR_NSH)
+ return false;
+
ovs_match_init(&match, &key, true, NULL);
- return !nsh_key_put_from_nlattr(attr, &match, false, true, log);
+ return !nsh_key_put_from_nlattr(nsh_key, &match, false, true, log);
}
/* Return false if there are any non-masked bits set.
@@ -3389,7 +3396,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
return -EINVAL;
}
mac_proto = MAC_PROTO_NONE;
- if (!validate_push_nsh(nla_data(a), log))
+ if (!validate_push_nsh(a, log))
return -EINVAL;
break;
--
2.52.0
From: Ilya Maximets <i.maximets(a)ovn.org>
[ Upstream commit 5ace7ef87f059d68b5f50837ef3e8a1a4870c36e ]
The push_nsh() action structure looks like this:
OVS_ACTION_ATTR_PUSH_NSH(OVS_KEY_ATTR_NSH(OVS_NSH_KEY_ATTR_BASE,...))
The outermost OVS_ACTION_ATTR_PUSH_NSH attribute is OK'ed by the
nla_for_each_nested() inside __ovs_nla_copy_actions(). The innermost
OVS_NSH_KEY_ATTR_BASE/MD1/MD2 are OK'ed by the nla_for_each_nested()
inside nsh_key_put_from_nlattr(). But nothing checks if the attribute
in the middle is OK. We don't even check that this attribute is the
OVS_KEY_ATTR_NSH. We just do a double unwrap with a pair of nla_data()
calls - first time directly while calling validate_push_nsh() and the
second time as part of the nla_for_each_nested() macro, which isn't
safe, potentially causing invalid memory access if the size of this
attribute is incorrect. The failure may not be noticed during
validation due to larger netlink buffer, but cause trouble later during
action execution where the buffer is allocated exactly to the size:
BUG: KASAN: slab-out-of-bounds in nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch]
Read of size 184 at addr ffff88816459a634 by task a.out/22624
CPU: 8 UID: 0 PID: 22624 6.18.0-rc7+ #115 PREEMPT(voluntary)
Call Trace:
<TASK>
dump_stack_lvl+0x51/0x70
print_address_description.constprop.0+0x2c/0x390
kasan_report+0xdd/0x110
kasan_check_range+0x35/0x1b0
__asan_memcpy+0x20/0x60
nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch]
push_nsh+0x82/0x120 [openvswitch]
do_execute_actions+0x1405/0x2840 [openvswitch]
ovs_execute_actions+0xd5/0x3b0 [openvswitch]
ovs_packet_cmd_execute+0x949/0xdb0 [openvswitch]
genl_family_rcv_msg_doit+0x1d6/0x2b0
genl_family_rcv_msg+0x336/0x580
genl_rcv_msg+0x9f/0x130
netlink_rcv_skb+0x11f/0x370
genl_rcv+0x24/0x40
netlink_unicast+0x73e/0xaa0
netlink_sendmsg+0x744/0xbf0
__sys_sendto+0x3d6/0x450
do_syscall_64+0x79/0x2c0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
</TASK>
Let's add some checks that the attribute is properly sized and it's
the only one attribute inside the action. Technically, there is no
real reason for OVS_KEY_ATTR_NSH to be there, as we know that we're
pushing an NSH header already, it just creates extra nesting, but
that's how uAPI works today. So, keeping as it is.
Fixes: b2d0f5d5dc53 ("openvswitch: enable NSH support")
Reported-by: Junvy Yang <zhuque(a)tencent.com>
Signed-off-by: Ilya Maximets <i.maximets(a)ovn.org>
Acked-by: Eelco Chaudron <echaudro(a)redhat.com>
Reviewed-by: Aaron Conole <aconole(a)redhat.com>
Link: https://patch.msgid.link/20251204105334.900379-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski <kuba(a)kernel.org>
(cherry picked from commit 5ace7ef87f059d68b5f50837ef3e8a1a4870c36e)
Signed-off-by: Adrian Yip <adrian.ytw(a)gmail.com>
---
net/openvswitch/flow_netlink.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index e3359e15aa2e..7d5490ea23e1 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -2802,13 +2802,20 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
return err;
}
-static bool validate_push_nsh(const struct nlattr *attr, bool log)
+static bool validate_push_nsh(const struct nlattr *a, bool log)
{
+ struct nlattr *nsh_key = nla_data(a);
struct sw_flow_match match;
struct sw_flow_key key;
+ /* There must be one and only one NSH header. */
+ if (!nla_ok(nsh_key, nla_len(a)) ||
+ nla_total_size(nla_len(nsh_key)) != nla_len(a) ||
+ nla_type(nsh_key) != OVS_KEY_ATTR_NSH)
+ return false;
+
ovs_match_init(&match, &key, true, NULL);
- return !nsh_key_put_from_nlattr(attr, &match, false, true, log);
+ return !nsh_key_put_from_nlattr(nsh_key, &match, false, true, log);
}
/* Return false if there are any non-masked bits set.
@@ -3388,7 +3395,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
return -EINVAL;
}
mac_proto = MAC_PROTO_NONE;
- if (!validate_push_nsh(nla_data(a), log))
+ if (!validate_push_nsh(a, log))
return -EINVAL;
break;
--
2.52.0
This reverts commit b3b274bc9d3d7307308aeaf75f70731765ac999a.
On the DragonBoard 820c (which uses APQ8096/MSM8996) this change causes
the CPUs to downclock to roughly half speed under sustained load. The
regression is visible both during boot and when running CPU stress
workloads such as stress-ng: the CPUs initially ramp up to the expected
frequency, then drop to a lower OPP even though the system is clearly
CPU-bound.
Bisecting points to this commit and reverting it restores the expected
behaviour on the DragonBoard 820c - the CPUs track the cpufreq policy
and run at full performance under load.
The exact interaction with the ACD is not yet fully understood and we
would like to keep ACD in use to avoid possible SoC reliability issues.
Until we have a better fix that preserves ACD while avoiding this
performance regression, revert the bisected patch to restore the
previous behaviour.
Fixes: b3b274bc9d3d ("clk: qcom: cpu-8996: simplify the cpu_clk_notifier_cb")
Cc: stable(a)vger.kernel.org # v6.3+
Link: https://lore.kernel.org/linux-arm-msm/20230113120544.59320-8-dmitry.baryshk…
Cc: Dmitry Baryshkov <dmitry.baryshkov(a)oss.qualcomm.com>
Signed-off-by: Christopher Obbard <christopher.obbard(a)linaro.org>
---
Hi all,
This series contains a single revert for a regression affecting the
APQ8096/MSM8996 (DragonBoard 820c).
The commit being reverted, b3b274bc9d3d ("clk: qcom: cpu-8996: simplify the cpu_clk_notifier_cb"),
introduces a significant performance issue where the CPUs downclock to
~50% of their expected frequency under sustained load. The problem is
reproducible both at boot and when running CPU-bound workloads such as
stress-ng.
Bisecting the issue pointed directly to this commit and reverting it
restores correct cpufreq behaviour.
The root cause appears to be related to the interaction between the
simplified notifier callback and ACD (Adaptive Clock Distribution).
Since we would prefer to keep ACD enabled for SoC reliability reasons,
a revert is the safest option until a proper fix is identified.
Full details are included in the commit message.
Feedback & suggestions welcome.
Cheers!
Christopher Obbard
---
drivers/clk/qcom/clk-cpu-8996.c | 30 +++++++++++-------------------
1 file changed, 11 insertions(+), 19 deletions(-)
diff --git a/drivers/clk/qcom/clk-cpu-8996.c b/drivers/clk/qcom/clk-cpu-8996.c
index 21d13c0841ed..028476931747 100644
--- a/drivers/clk/qcom/clk-cpu-8996.c
+++ b/drivers/clk/qcom/clk-cpu-8996.c
@@ -547,35 +547,27 @@ static int cpu_clk_notifier_cb(struct notifier_block *nb, unsigned long event,
{
struct clk_cpu_8996_pmux *cpuclk = to_clk_cpu_8996_pmux_nb(nb);
struct clk_notifier_data *cnd = data;
+ int ret;
switch (event) {
case PRE_RATE_CHANGE:
+ ret = clk_cpu_8996_pmux_set_parent(&cpuclk->clkr.hw, ALT_INDEX);
qcom_cpu_clk_msm8996_acd_init(cpuclk->clkr.regmap);
-
- /*
- * Avoid overvolting. clk_core_set_rate_nolock() walks from top
- * to bottom, so it will change the rate of the PLL before
- * chaging the parent of PMUX. This can result in pmux getting
- * clocked twice the expected rate.
- *
- * Manually switch to PLL/2 here.
- */
- if (cnd->new_rate < DIV_2_THRESHOLD &&
- cnd->old_rate > DIV_2_THRESHOLD)
- clk_cpu_8996_pmux_set_parent(&cpuclk->clkr.hw, SMUX_INDEX);
-
break;
- case ABORT_RATE_CHANGE:
- /* Revert manual change */
- if (cnd->new_rate < DIV_2_THRESHOLD &&
- cnd->old_rate > DIV_2_THRESHOLD)
- clk_cpu_8996_pmux_set_parent(&cpuclk->clkr.hw, ACD_INDEX);
+ case POST_RATE_CHANGE:
+ if (cnd->new_rate < DIV_2_THRESHOLD)
+ ret = clk_cpu_8996_pmux_set_parent(&cpuclk->clkr.hw,
+ SMUX_INDEX);
+ else
+ ret = clk_cpu_8996_pmux_set_parent(&cpuclk->clkr.hw,
+ ACD_INDEX);
break;
default:
+ ret = 0;
break;
}
- return NOTIFY_OK;
+ return notifier_from_errno(ret);
};
static int qcom_cpu_clk_msm8996_driver_probe(struct platform_device *pdev)
---
base-commit: c17e270dfb342a782d69c4a7c4c32980455afd9c
change-id: 20251202-wip-obbardc-qcom-msm8096-clk-cpu-fix-downclock-b7561da4cb95
Best regards,
--
Christopher Obbard <christopher.obbard(a)linaro.org>
When dma_iova_link() fails partway through mapping a request's
bvec list, the function breaks out of the loop without cleaning up the
already-mapped portions. Similarly, if dma_iova_sync() fails after all
segments are linked, no cleanup is performed.
This leaves the IOVA state partially mapped. The completion path
(via dma_iova_destroy() or nvme_unmap_data()) then attempts to unmap
the full expected size, but only a partial size was actually mapped.
Fix by adding an out_unlink error path that calls dma_iova_destroy()
to clean up any partial mapping before returning failure. The
dma_iova_destroy() function handles both partial unlink and IOVA space
freeing, and correctly handles the case where mapped_len is zero
(first dma_iova_link() failed) by just freeing the IOVA allocation.
This ensures that when an error occurs:
1. All partially-mapped IOVA ranges are properly unmapped
2. The IOVA address space is freed
3. The completion path won't attempt to unmap non-existent mappings
Fixes: 858299dc6160 ("block: add scatterlist-less DMA mapping helpers")
Cc: stable(a)vger.kernel.org
Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux(a)gmail.com>
---
Hi Leon,
Your last email is not accessible to me.
Updated the patch description to explain dma_iova_destroy().
Please let me know for any issues you want me to fix before I send.
-ck
---
block/blk-mq-dma.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/block/blk-mq-dma.c b/block/blk-mq-dma.c
index fb018fffffdc..feead1934301 100644
--- a/block/blk-mq-dma.c
+++ b/block/blk-mq-dma.c
@@ -126,17 +126,20 @@ static bool blk_rq_dma_map_iova(struct request *req, struct device *dma_dev,
error = dma_iova_link(dma_dev, state, vec->paddr, mapped,
vec->len, dir, attrs);
if (error)
- break;
+ goto out_unlink;
mapped += vec->len;
} while (blk_map_iter_next(req, &iter->iter, vec));
error = dma_iova_sync(dma_dev, state, 0, mapped);
- if (error) {
- iter->status = errno_to_blk_status(error);
- return false;
- }
+ if (error)
+ goto out_unlink;
return true;
+
+out_unlink:
+ dma_iova_destroy(dma_dev, state, mapped, dir, attrs);
+ iter->status = errno_to_blk_status(error);
+ return false;
}
static inline void blk_rq_map_iter_init(struct request *rq,
--
2.40.0
For a while, I've been seeing a strange issue where some (usually not all)
of the display DMA channels will suddenly hang, particularly when there is
a visible cursor on the screen that is being frequently updated, and
especially when said cursor happens to go between two screens. While this
brings back lovely memories of fixing Intel Skylake bugs, I would quite
like to fix it :).
It turns out the problem that's happening here is that we're managing to
reach nv50_head_flush_set() in our atomic commit path without actually
holding nv50_disp->mutex. This means that cursor updates happening in
parallel (along with any other atomic updates that need to use the core
channel) will race with eachother, which eventually causes us to corrupt
the pushbuffer - leading to a plethora of various GSP errors, usually:
nouveau 0000:c1:00.0: gsp: Xid:56 CMDre 00000000 00000218 00102680 00000004 00800003
nouveau 0000:c1:00.0: gsp: Xid:56 CMDre 00000000 0000021c 00040509 00000004 00000001
nouveau 0000:c1:00.0: gsp: Xid:56 CMDre 00000000 00000000 00000000 00000001 00000001
The reason this is happening is because generally we check whether we need
to set nv50_atom->lock_core at the end of nv50_head_atomic_check().
However, curs507a_prepare is called from the fb_prepare callback, which
happens after the atomic check phase. As a result, this can lead to commits
that both touch the core channel but also don't grab nv50_disp->mutex.
So, fix this by making sure that we set nv50_atom->lock_core in
cus507a_prepare().
Signed-off-by: Lyude Paul <lyude(a)redhat.com>
Fixes: 1590700d94ac ("drm/nouveau/kms/nv50-: split each resource type into their own source files")
Cc: <stable(a)vger.kernel.org> # v4.18+
---
drivers/gpu/drm/nouveau/dispnv50/curs507a.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/nouveau/dispnv50/curs507a.c b/drivers/gpu/drm/nouveau/dispnv50/curs507a.c
index a95ee5dcc2e39..1a889139cb053 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/curs507a.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/curs507a.c
@@ -84,6 +84,7 @@ curs507a_prepare(struct nv50_wndw *wndw, struct nv50_head_atom *asyh,
asyh->curs.handle = handle;
asyh->curs.offset = offset;
asyh->set.curs = asyh->curs.visible;
+ nv50_atom(asyh->state.state)->lock_core = true;
}
}
--
2.52.0