The patch below does not apply to the 4.19-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8126b1c73108bc691f5643df19071a59a69d0bc6 Mon Sep 17 00:00:00 2001
From: Jann Horn <jannh(a)google.com>
Date: Mon, 14 Mar 2022 19:59:53 +0100
Subject: [PATCH] pstore: Don't use semaphores in always-atomic-context code
pstore_dump() is *always* invoked in atomic context (nowadays in an RCU
read-side critical section, before that under a spinlock).
It doesn't make sense to try to use semaphores here.
This is mostly a revert of commit ea84b580b955 ("pstore: Convert buf_lock
to semaphore"), except that two parts aren't restored back exactly as they
were:
- keep the lock initialization in pstore_register
- in efi_pstore_write(), always set the "block" flag to false
- omit "is_locked", that was unnecessary since
commit 959217c84c27 ("pstore: Actually give up during locking failure")
- fix the bailout message
The actual problem that the buggy commit was trying to address may have
been that the use of preemptible() in efi_pstore_write() was wrong - it
only looks at preempt_count() and the state of IRQs, but __rcu_read_lock()
doesn't touch either of those under CONFIG_PREEMPT_RCU.
(Sidenote: CONFIG_PREEMPT_RCU means that the scheduler can preempt tasks in
RCU read-side critical sections, but you're not allowed to actively
block/reschedule.)
Lockdep probably never caught the problem because it's very rare that you
actually hit the contended case, so lockdep always just sees the
down_trylock(), not the down_interruptible(), and so it can't tell that
there's a problem.
Fixes: ea84b580b955 ("pstore: Convert buf_lock to semaphore")
Cc: stable(a)vger.kernel.org
Acked-by: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Signed-off-by: Jann Horn <jannh(a)google.com>
Signed-off-by: Kees Cook <keescook(a)chromium.org>
Link: https://lore.kernel.org/r/20220314185953.2068993-1-jannh@google.com
diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
index 0ef086e43090..7e771c56c13c 100644
--- a/drivers/firmware/efi/efi-pstore.c
+++ b/drivers/firmware/efi/efi-pstore.c
@@ -266,7 +266,7 @@ static int efi_pstore_write(struct pstore_record *record)
efi_name[i] = name[i];
ret = efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES,
- preemptible(), record->size, record->psi->buf);
+ false, record->size, record->psi->buf);
if (record->reason == KMSG_DUMP_OOPS && try_module_get(THIS_MODULE))
if (!schedule_work(&efivar_work))
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index f243cb5e6a4f..e26162f102ff 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -143,21 +143,22 @@ static void pstore_timer_kick(void)
mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
}
-/*
- * Should pstore_dump() wait for a concurrent pstore_dump()? If
- * not, the current pstore_dump() will report a failure to dump
- * and return.
- */
-static bool pstore_cannot_wait(enum kmsg_dump_reason reason)
+static bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
{
- /* In NMI path, pstore shouldn't block regardless of reason. */
+ /*
+ * In case of NMI path, pstore shouldn't be blocked
+ * regardless of reason.
+ */
if (in_nmi())
return true;
switch (reason) {
/* In panic case, other cpus are stopped by smp_send_stop(). */
case KMSG_DUMP_PANIC:
- /* Emergency restart shouldn't be blocked. */
+ /*
+ * Emergency restart shouldn't be blocked by spinning on
+ * pstore_info::buf_lock.
+ */
case KMSG_DUMP_EMERG:
return true;
default:
@@ -389,21 +390,19 @@ static void pstore_dump(struct kmsg_dumper *dumper,
unsigned long total = 0;
const char *why;
unsigned int part = 1;
+ unsigned long flags = 0;
int ret;
why = kmsg_dump_reason_str(reason);
- if (down_trylock(&psinfo->buf_lock)) {
- /* Failed to acquire lock: give up if we cannot wait. */
- if (pstore_cannot_wait(reason)) {
- pr_err("dump skipped in %s path: may corrupt error record\n",
- in_nmi() ? "NMI" : why);
- return;
- }
- if (down_interruptible(&psinfo->buf_lock)) {
- pr_err("could not grab semaphore?!\n");
+ if (pstore_cannot_block_path(reason)) {
+ if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
+ pr_err("dump skipped in %s path because of concurrent dump\n",
+ in_nmi() ? "NMI" : why);
return;
}
+ } else {
+ spin_lock_irqsave(&psinfo->buf_lock, flags);
}
kmsg_dump_rewind(&iter);
@@ -467,8 +466,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
total += record.size;
part++;
}
-
- up(&psinfo->buf_lock);
+ spin_unlock_irqrestore(&psinfo->buf_lock, flags);
}
static struct kmsg_dumper pstore_dumper = {
@@ -594,7 +592,7 @@ int pstore_register(struct pstore_info *psi)
psi->write_user = pstore_write_user_compat;
psinfo = psi;
mutex_init(&psinfo->read_mutex);
- sema_init(&psinfo->buf_lock, 1);
+ spin_lock_init(&psinfo->buf_lock);
if (psi->flags & PSTORE_FLAGS_DMESG)
allocate_buf_for_compression();
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index eb93a54cff31..e97a8188f0fd 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -14,7 +14,7 @@
#include <linux/errno.h>
#include <linux/kmsg_dump.h>
#include <linux/mutex.h>
-#include <linux/semaphore.h>
+#include <linux/spinlock.h>
#include <linux/time.h>
#include <linux/types.h>
@@ -87,7 +87,7 @@ struct pstore_record {
* @owner: module which is responsible for this backend driver
* @name: name of the backend driver
*
- * @buf_lock: semaphore to serialize access to @buf
+ * @buf_lock: spinlock to serialize access to @buf
* @buf: preallocated crash dump buffer
* @bufsize: size of @buf available for crash dump bytes (must match
* smallest number of bytes available for writing to a
@@ -178,7 +178,7 @@ struct pstore_info {
struct module *owner;
const char *name;
- struct semaphore buf_lock;
+ spinlock_t buf_lock;
char *buf;
size_t bufsize;
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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8126b1c73108bc691f5643df19071a59a69d0bc6 Mon Sep 17 00:00:00 2001
From: Jann Horn <jannh(a)google.com>
Date: Mon, 14 Mar 2022 19:59:53 +0100
Subject: [PATCH] pstore: Don't use semaphores in always-atomic-context code
pstore_dump() is *always* invoked in atomic context (nowadays in an RCU
read-side critical section, before that under a spinlock).
It doesn't make sense to try to use semaphores here.
This is mostly a revert of commit ea84b580b955 ("pstore: Convert buf_lock
to semaphore"), except that two parts aren't restored back exactly as they
were:
- keep the lock initialization in pstore_register
- in efi_pstore_write(), always set the "block" flag to false
- omit "is_locked", that was unnecessary since
commit 959217c84c27 ("pstore: Actually give up during locking failure")
- fix the bailout message
The actual problem that the buggy commit was trying to address may have
been that the use of preemptible() in efi_pstore_write() was wrong - it
only looks at preempt_count() and the state of IRQs, but __rcu_read_lock()
doesn't touch either of those under CONFIG_PREEMPT_RCU.
(Sidenote: CONFIG_PREEMPT_RCU means that the scheduler can preempt tasks in
RCU read-side critical sections, but you're not allowed to actively
block/reschedule.)
Lockdep probably never caught the problem because it's very rare that you
actually hit the contended case, so lockdep always just sees the
down_trylock(), not the down_interruptible(), and so it can't tell that
there's a problem.
Fixes: ea84b580b955 ("pstore: Convert buf_lock to semaphore")
Cc: stable(a)vger.kernel.org
Acked-by: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Signed-off-by: Jann Horn <jannh(a)google.com>
Signed-off-by: Kees Cook <keescook(a)chromium.org>
Link: https://lore.kernel.org/r/20220314185953.2068993-1-jannh@google.com
diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
index 0ef086e43090..7e771c56c13c 100644
--- a/drivers/firmware/efi/efi-pstore.c
+++ b/drivers/firmware/efi/efi-pstore.c
@@ -266,7 +266,7 @@ static int efi_pstore_write(struct pstore_record *record)
efi_name[i] = name[i];
ret = efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES,
- preemptible(), record->size, record->psi->buf);
+ false, record->size, record->psi->buf);
if (record->reason == KMSG_DUMP_OOPS && try_module_get(THIS_MODULE))
if (!schedule_work(&efivar_work))
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index f243cb5e6a4f..e26162f102ff 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -143,21 +143,22 @@ static void pstore_timer_kick(void)
mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
}
-/*
- * Should pstore_dump() wait for a concurrent pstore_dump()? If
- * not, the current pstore_dump() will report a failure to dump
- * and return.
- */
-static bool pstore_cannot_wait(enum kmsg_dump_reason reason)
+static bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
{
- /* In NMI path, pstore shouldn't block regardless of reason. */
+ /*
+ * In case of NMI path, pstore shouldn't be blocked
+ * regardless of reason.
+ */
if (in_nmi())
return true;
switch (reason) {
/* In panic case, other cpus are stopped by smp_send_stop(). */
case KMSG_DUMP_PANIC:
- /* Emergency restart shouldn't be blocked. */
+ /*
+ * Emergency restart shouldn't be blocked by spinning on
+ * pstore_info::buf_lock.
+ */
case KMSG_DUMP_EMERG:
return true;
default:
@@ -389,21 +390,19 @@ static void pstore_dump(struct kmsg_dumper *dumper,
unsigned long total = 0;
const char *why;
unsigned int part = 1;
+ unsigned long flags = 0;
int ret;
why = kmsg_dump_reason_str(reason);
- if (down_trylock(&psinfo->buf_lock)) {
- /* Failed to acquire lock: give up if we cannot wait. */
- if (pstore_cannot_wait(reason)) {
- pr_err("dump skipped in %s path: may corrupt error record\n",
- in_nmi() ? "NMI" : why);
- return;
- }
- if (down_interruptible(&psinfo->buf_lock)) {
- pr_err("could not grab semaphore?!\n");
+ if (pstore_cannot_block_path(reason)) {
+ if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
+ pr_err("dump skipped in %s path because of concurrent dump\n",
+ in_nmi() ? "NMI" : why);
return;
}
+ } else {
+ spin_lock_irqsave(&psinfo->buf_lock, flags);
}
kmsg_dump_rewind(&iter);
@@ -467,8 +466,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
total += record.size;
part++;
}
-
- up(&psinfo->buf_lock);
+ spin_unlock_irqrestore(&psinfo->buf_lock, flags);
}
static struct kmsg_dumper pstore_dumper = {
@@ -594,7 +592,7 @@ int pstore_register(struct pstore_info *psi)
psi->write_user = pstore_write_user_compat;
psinfo = psi;
mutex_init(&psinfo->read_mutex);
- sema_init(&psinfo->buf_lock, 1);
+ spin_lock_init(&psinfo->buf_lock);
if (psi->flags & PSTORE_FLAGS_DMESG)
allocate_buf_for_compression();
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index eb93a54cff31..e97a8188f0fd 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -14,7 +14,7 @@
#include <linux/errno.h>
#include <linux/kmsg_dump.h>
#include <linux/mutex.h>
-#include <linux/semaphore.h>
+#include <linux/spinlock.h>
#include <linux/time.h>
#include <linux/types.h>
@@ -87,7 +87,7 @@ struct pstore_record {
* @owner: module which is responsible for this backend driver
* @name: name of the backend driver
*
- * @buf_lock: semaphore to serialize access to @buf
+ * @buf_lock: spinlock to serialize access to @buf
* @buf: preallocated crash dump buffer
* @bufsize: size of @buf available for crash dump bytes (must match
* smallest number of bytes available for writing to a
@@ -178,7 +178,7 @@ struct pstore_info {
struct module *owner;
const char *name;
- struct semaphore buf_lock;
+ spinlock_t buf_lock;
char *buf;
size_t bufsize;
The patch below does not apply to the 5.17-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7344bad7fb6daa4877a1c064b52c7d5f9182c41b Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula(a)intel.com>
Date: Wed, 23 Mar 2022 12:04:38 +0200
Subject: [PATCH] drm/edid: fix CEA extension byte #3 parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Only an EDID CEA extension has byte #3, while the CTA DisplayID Data
Block does not. Don't interpret bogus data for color formats.
For most displays it's probably an unlikely scenario you'd have a CTA
DisplayID Data Block without a CEA extension, but they do exist.
Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID")
Cc: <stable(a)vger.kernel.org>
Cc: Shawn C Lee <shawn.c.lee(a)intel.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula(a)intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323100438.1757295-1-jani…
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f07af6786cec..cc7bd58369df 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5188,10 +5188,14 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
/* The existence of a CEA block should imply RGB support */
info->color_formats = DRM_COLOR_FORMAT_RGB444;
- if (edid_ext[3] & EDID_CEA_YCRCB444)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
- if (edid_ext[3] & EDID_CEA_YCRCB422)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+
+ /* CTA DisplayID Data Block does not have byte #3 */
+ if (edid_ext[0] == CEA_EXT) {
+ if (edid_ext[3] & EDID_CEA_YCRCB444)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
+ if (edid_ext[3] & EDID_CEA_YCRCB422)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+ }
if (cea_db_offsets(edid_ext, &start, &end))
return;
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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7344bad7fb6daa4877a1c064b52c7d5f9182c41b Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula(a)intel.com>
Date: Wed, 23 Mar 2022 12:04:38 +0200
Subject: [PATCH] drm/edid: fix CEA extension byte #3 parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Only an EDID CEA extension has byte #3, while the CTA DisplayID Data
Block does not. Don't interpret bogus data for color formats.
For most displays it's probably an unlikely scenario you'd have a CTA
DisplayID Data Block without a CEA extension, but they do exist.
Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID")
Cc: <stable(a)vger.kernel.org>
Cc: Shawn C Lee <shawn.c.lee(a)intel.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula(a)intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323100438.1757295-1-jani…
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f07af6786cec..cc7bd58369df 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5188,10 +5188,14 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
/* The existence of a CEA block should imply RGB support */
info->color_formats = DRM_COLOR_FORMAT_RGB444;
- if (edid_ext[3] & EDID_CEA_YCRCB444)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
- if (edid_ext[3] & EDID_CEA_YCRCB422)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+
+ /* CTA DisplayID Data Block does not have byte #3 */
+ if (edid_ext[0] == CEA_EXT) {
+ if (edid_ext[3] & EDID_CEA_YCRCB444)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
+ if (edid_ext[3] & EDID_CEA_YCRCB422)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+ }
if (cea_db_offsets(edid_ext, &start, &end))
return;
The patch below does not apply to the 5.16-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7344bad7fb6daa4877a1c064b52c7d5f9182c41b Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula(a)intel.com>
Date: Wed, 23 Mar 2022 12:04:38 +0200
Subject: [PATCH] drm/edid: fix CEA extension byte #3 parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Only an EDID CEA extension has byte #3, while the CTA DisplayID Data
Block does not. Don't interpret bogus data for color formats.
For most displays it's probably an unlikely scenario you'd have a CTA
DisplayID Data Block without a CEA extension, but they do exist.
Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID")
Cc: <stable(a)vger.kernel.org>
Cc: Shawn C Lee <shawn.c.lee(a)intel.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula(a)intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323100438.1757295-1-jani…
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f07af6786cec..cc7bd58369df 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5188,10 +5188,14 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
/* The existence of a CEA block should imply RGB support */
info->color_formats = DRM_COLOR_FORMAT_RGB444;
- if (edid_ext[3] & EDID_CEA_YCRCB444)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
- if (edid_ext[3] & EDID_CEA_YCRCB422)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+
+ /* CTA DisplayID Data Block does not have byte #3 */
+ if (edid_ext[0] == CEA_EXT) {
+ if (edid_ext[3] & EDID_CEA_YCRCB444)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
+ if (edid_ext[3] & EDID_CEA_YCRCB422)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+ }
if (cea_db_offsets(edid_ext, &start, &end))
return;
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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7344bad7fb6daa4877a1c064b52c7d5f9182c41b Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula(a)intel.com>
Date: Wed, 23 Mar 2022 12:04:38 +0200
Subject: [PATCH] drm/edid: fix CEA extension byte #3 parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Only an EDID CEA extension has byte #3, while the CTA DisplayID Data
Block does not. Don't interpret bogus data for color formats.
For most displays it's probably an unlikely scenario you'd have a CTA
DisplayID Data Block without a CEA extension, but they do exist.
Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID")
Cc: <stable(a)vger.kernel.org>
Cc: Shawn C Lee <shawn.c.lee(a)intel.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula(a)intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323100438.1757295-1-jani…
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f07af6786cec..cc7bd58369df 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5188,10 +5188,14 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
/* The existence of a CEA block should imply RGB support */
info->color_formats = DRM_COLOR_FORMAT_RGB444;
- if (edid_ext[3] & EDID_CEA_YCRCB444)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
- if (edid_ext[3] & EDID_CEA_YCRCB422)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+
+ /* CTA DisplayID Data Block does not have byte #3 */
+ if (edid_ext[0] == CEA_EXT) {
+ if (edid_ext[3] & EDID_CEA_YCRCB444)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
+ if (edid_ext[3] & EDID_CEA_YCRCB422)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+ }
if (cea_db_offsets(edid_ext, &start, &end))
return;
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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7344bad7fb6daa4877a1c064b52c7d5f9182c41b Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula(a)intel.com>
Date: Wed, 23 Mar 2022 12:04:38 +0200
Subject: [PATCH] drm/edid: fix CEA extension byte #3 parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Only an EDID CEA extension has byte #3, while the CTA DisplayID Data
Block does not. Don't interpret bogus data for color formats.
For most displays it's probably an unlikely scenario you'd have a CTA
DisplayID Data Block without a CEA extension, but they do exist.
Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID")
Cc: <stable(a)vger.kernel.org>
Cc: Shawn C Lee <shawn.c.lee(a)intel.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula(a)intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323100438.1757295-1-jani…
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f07af6786cec..cc7bd58369df 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5188,10 +5188,14 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
/* The existence of a CEA block should imply RGB support */
info->color_formats = DRM_COLOR_FORMAT_RGB444;
- if (edid_ext[3] & EDID_CEA_YCRCB444)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
- if (edid_ext[3] & EDID_CEA_YCRCB422)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+
+ /* CTA DisplayID Data Block does not have byte #3 */
+ if (edid_ext[0] == CEA_EXT) {
+ if (edid_ext[3] & EDID_CEA_YCRCB444)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
+ if (edid_ext[3] & EDID_CEA_YCRCB422)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+ }
if (cea_db_offsets(edid_ext, &start, &end))
return;
The patch below does not apply to the 4.19-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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 7344bad7fb6daa4877a1c064b52c7d5f9182c41b Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula(a)intel.com>
Date: Wed, 23 Mar 2022 12:04:38 +0200
Subject: [PATCH] drm/edid: fix CEA extension byte #3 parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Only an EDID CEA extension has byte #3, while the CTA DisplayID Data
Block does not. Don't interpret bogus data for color formats.
For most displays it's probably an unlikely scenario you'd have a CTA
DisplayID Data Block without a CEA extension, but they do exist.
Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID")
Cc: <stable(a)vger.kernel.org>
Cc: Shawn C Lee <shawn.c.lee(a)intel.com>
Cc: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula(a)intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala(a)linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323100438.1757295-1-jani…
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index f07af6786cec..cc7bd58369df 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5188,10 +5188,14 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
/* The existence of a CEA block should imply RGB support */
info->color_formats = DRM_COLOR_FORMAT_RGB444;
- if (edid_ext[3] & EDID_CEA_YCRCB444)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
- if (edid_ext[3] & EDID_CEA_YCRCB422)
- info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+
+ /* CTA DisplayID Data Block does not have byte #3 */
+ if (edid_ext[0] == CEA_EXT) {
+ if (edid_ext[3] & EDID_CEA_YCRCB444)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR444;
+ if (edid_ext[3] & EDID_CEA_YCRCB422)
+ info->color_formats |= DRM_COLOR_FORMAT_YCBCR422;
+ }
if (cea_db_offsets(edid_ext, &start, &end))
return;
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>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From aa1b46dcdc7baaf5fec0be25782ef24b26aa209e Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj(a)kernel.org>
Date: Sun, 13 Mar 2022 21:15:02 -1000
Subject: [PATCH] block: fix rq-qos breakage from skipping rq_qos_done_bio()
a647a524a467 ("block: don't call rq_qos_ops->done_bio if the bio isn't
tracked") made bio_endio() skip rq_qos_done_bio() if BIO_TRACKED is not set.
While this fixed a potential oops, it also broke blk-iocost by skipping the
done_bio callback for merged bios.
Before, whether a bio goes through rq_qos_throttle() or rq_qos_merge(),
rq_qos_done_bio() would be called on the bio on completion with BIO_TRACKED
distinguishing the former from the latter. rq_qos_done_bio() is not called
for bios which wenth through rq_qos_merge(). This royally confuses
blk-iocost as the merged bios never finish and are considered perpetually
in-flight.
One reliably reproducible failure mode is an intermediate cgroup geting
stuck active preventing its children from being activated due to the
leaf-only rule, leading to loss of control. The following is from
resctl-bench protection scenario which emulates isolating a web server like
workload from a memory bomb run on an iocost configuration which should
yield a reasonable level of protection.
# cat /sys/block/nvme2n1/device/model
Samsung SSD 970 PRO 512GB
# cat /sys/fs/cgroup/io.cost.model
259:0 ctrl=user model=linear rbps=834913556 rseqiops=93622 rrandiops=102913 wbps=618985353 wseqiops=72325 wrandiops=71025
# cat /sys/fs/cgroup/io.cost.qos
259:0 enable=1 ctrl=user rpct=95.00 rlat=18776 wpct=95.00 wlat=8897 min=60.00 max=100.00
# resctl-bench -m 29.6G -r out.json run protection::scenario=mem-hog,loops=1
...
Memory Hog Summary
==================
IO Latency: R p50=242u:336u/2.5m p90=794u:1.4m/7.5m p99=2.7m:8.0m/62.5m max=8.0m:36.4m/350m
W p50=221u:323u/1.5m p90=709u:1.2m/5.5m p99=1.5m:2.5m/9.5m max=6.9m:35.9m/350m
Isolation and Request Latency Impact Distributions:
min p01 p05 p10 p25 p50 p75 p90 p95 p99 max mean stdev
isol% 15.90 15.90 15.90 40.05 57.24 59.07 60.01 74.63 74.63 90.35 90.35 58.12 15.82
lat-imp% 0 0 0 0 0 4.55 14.68 15.54 233.5 548.1 548.1 53.88 143.6
Result: isol=58.12:15.82% lat_imp=53.88%:143.6 work_csv=100.0% missing=3.96%
The isolation result of 58.12% is close to what this device would show
without any IO control.
Fix it by introducing a new flag BIO_QOS_MERGED to mark merged bios and
calling rq_qos_done_bio() on them too. For consistency and clarity, rename
BIO_TRACKED to BIO_QOS_THROTTLED. The flag checks are moved into
rq_qos_done_bio() so that it's next to the code paths that set the flags.
With the patch applied, the above same benchmark shows:
# resctl-bench -m 29.6G -r out.json run protection::scenario=mem-hog,loops=1
...
Memory Hog Summary
==================
IO Latency: R p50=123u:84.4u/985u p90=322u:256u/2.5m p99=1.6m:1.4m/9.5m max=11.1m:36.0m/350m
W p50=429u:274u/995u p90=1.7m:1.3m/4.5m p99=3.4m:2.7m/11.5m max=7.9m:5.9m/26.5m
Isolation and Request Latency Impact Distributions:
min p01 p05 p10 p25 p50 p75 p90 p95 p99 max mean stdev
isol% 84.91 84.91 89.51 90.73 92.31 94.49 96.36 98.04 98.71 100.0 100.0 94.42 2.81
lat-imp% 0 0 0 0 0 2.81 5.73 11.11 13.92 17.53 22.61 4.10 4.68
Result: isol=94.42:2.81% lat_imp=4.10%:4.68 work_csv=58.34% missing=0%
Signed-off-by: Tejun Heo <tj(a)kernel.org>
Fixes: a647a524a467 ("block: don't call rq_qos_ops->done_bio if the bio isn't tracked")
Cc: stable(a)vger.kernel.org # v5.15+
Cc: Ming Lei <ming.lei(a)redhat.com>
Cc: Yu Kuai <yukuai3(a)huawei.com>
Reviewed-by: Ming Lei <ming.lei(a)redhat.com>
Link: https://lore.kernel.org/r/Yi7rdrzQEHjJLGKB@slm.duckdns.org
Signed-off-by: Jens Axboe <axboe(a)kernel.dk>
diff --git a/block/bio.c b/block/bio.c
index 151cace2dbe1..33979f306e9e 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1516,8 +1516,7 @@ void bio_endio(struct bio *bio)
if (!bio_integrity_endio(bio))
return;
- if (bio->bi_bdev && bio_flagged(bio, BIO_TRACKED))
- rq_qos_done_bio(bdev_get_queue(bio->bi_bdev), bio);
+ rq_qos_done_bio(bio);
if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
trace_block_bio_complete(bdev_get_queue(bio->bi_bdev), bio);
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 010e658d44a8..2f33932e72e3 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -598,7 +598,7 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
int inflight = 0;
blkg = bio->bi_blkg;
- if (!blkg || !bio_flagged(bio, BIO_TRACKED))
+ if (!blkg || !bio_flagged(bio, BIO_QOS_THROTTLED))
return;
iolat = blkg_to_lat(bio->bi_blkg);
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index 3cfbc8668cba..68267007da1c 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -177,20 +177,20 @@ static inline void rq_qos_requeue(struct request_queue *q, struct request *rq)
__rq_qos_requeue(q->rq_qos, rq);
}
-static inline void rq_qos_done_bio(struct request_queue *q, struct bio *bio)
+static inline void rq_qos_done_bio(struct bio *bio)
{
- if (q->rq_qos)
- __rq_qos_done_bio(q->rq_qos, bio);
+ if (bio->bi_bdev && (bio_flagged(bio, BIO_QOS_THROTTLED) ||
+ bio_flagged(bio, BIO_QOS_MERGED))) {
+ struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+ if (q->rq_qos)
+ __rq_qos_done_bio(q->rq_qos, bio);
+ }
}
static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
{
- /*
- * BIO_TRACKED lets controllers know that a bio went through the
- * normal rq_qos path.
- */
if (q->rq_qos) {
- bio_set_flag(bio, BIO_TRACKED);
+ bio_set_flag(bio, BIO_QOS_THROTTLED);
__rq_qos_throttle(q->rq_qos, bio);
}
}
@@ -205,8 +205,10 @@ static inline void rq_qos_track(struct request_queue *q, struct request *rq,
static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
struct bio *bio)
{
- if (q->rq_qos)
+ if (q->rq_qos) {
+ bio_set_flag(bio, BIO_QOS_MERGED);
__rq_qos_merge(q->rq_qos, rq, bio);
+ }
}
static inline void rq_qos_queue_depth_changed(struct request_queue *q)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 5561e58d158a..0c3563b45fe9 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -324,7 +324,8 @@ enum {
BIO_TRACE_COMPLETION, /* bio_endio() should trace the final completion
* of this bio. */
BIO_CGROUP_ACCT, /* has been accounted to a cgroup */
- BIO_TRACKED, /* set if bio goes through the rq_qos path */
+ BIO_QOS_THROTTLED, /* bio went through rq_qos throttle path */
+ BIO_QOS_MERGED, /* but went through rq_qos merge path */
BIO_REMAPPED,
BIO_ZONE_WRITE_LOCKED, /* Owns a zoned device zone write lock */
BIO_PERCPU_CACHE, /* can participate in per-cpu alloc cache */