The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 8dfcffa37094fef2c8cf8b602316766a86956d07
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024073034-regulator-impatient-bbba@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
8dfcffa37094 ("Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"")
9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8dfcffa37094fef2c8cf8b602316766a86956d07 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Fri, 21 Jun 2024 16:42:37 +0200
Subject: [PATCH] Revert "mm/writeback: fix possible divide-by-zero in
wb_dirty_limits(), again"
Patch series "mm: Avoid possible overflows in dirty throttling".
Dirty throttling logic assumes dirty limits in page units fit into
32-bits. This patch series makes sure this is true (see patch 2/2 for
more details).
This patch (of 2):
This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78.
The commit is broken in several ways. Firstly, the removed (u64) cast
from the multiplication will introduce a multiplication overflow on 32-bit
archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the
default settings with 4GB of RAM will trigger this). Secondly, the
div64_u64() is unnecessarily expensive on 32-bit archs. We have
div64_ul() in case we want to be safe & cheap. Thirdly, if dirty
thresholds are larger than 1<<32 pages, then dirty balancing is going to
blow up in many other spectacular ways anyway so trying to fix one
possible overflow is just moot.
Link: https://lkml.kernel.org/r/20240621144017.30993-1-jack@suse.cz
Link: https://lkml.kernel.org/r/20240621144246.11148-1-jack@suse.cz
Fixes: 9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
Signed-off-by: Jan Kara <jack(a)suse.cz>
Reviewed-By: Zach O'Keefe <zokeefe(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7168e25f88e5..c4aa6e84c20a 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1683,7 +1683,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
*/
dtc->wb_thresh = __wb_calc_thresh(dtc, dtc->thresh);
dtc->wb_bg_thresh = dtc->thresh ?
- div64_u64(dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
+ div_u64((u64)dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
/*
* In order to avoid the stacked BDI deadlock we need
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 8dfcffa37094fef2c8cf8b602316766a86956d07
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024073033-riverbed-nutcase-30ab@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
8dfcffa37094 ("Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"")
9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8dfcffa37094fef2c8cf8b602316766a86956d07 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Fri, 21 Jun 2024 16:42:37 +0200
Subject: [PATCH] Revert "mm/writeback: fix possible divide-by-zero in
wb_dirty_limits(), again"
Patch series "mm: Avoid possible overflows in dirty throttling".
Dirty throttling logic assumes dirty limits in page units fit into
32-bits. This patch series makes sure this is true (see patch 2/2 for
more details).
This patch (of 2):
This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78.
The commit is broken in several ways. Firstly, the removed (u64) cast
from the multiplication will introduce a multiplication overflow on 32-bit
archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the
default settings with 4GB of RAM will trigger this). Secondly, the
div64_u64() is unnecessarily expensive on 32-bit archs. We have
div64_ul() in case we want to be safe & cheap. Thirdly, if dirty
thresholds are larger than 1<<32 pages, then dirty balancing is going to
blow up in many other spectacular ways anyway so trying to fix one
possible overflow is just moot.
Link: https://lkml.kernel.org/r/20240621144017.30993-1-jack@suse.cz
Link: https://lkml.kernel.org/r/20240621144246.11148-1-jack@suse.cz
Fixes: 9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
Signed-off-by: Jan Kara <jack(a)suse.cz>
Reviewed-By: Zach O'Keefe <zokeefe(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7168e25f88e5..c4aa6e84c20a 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1683,7 +1683,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
*/
dtc->wb_thresh = __wb_calc_thresh(dtc, dtc->thresh);
dtc->wb_bg_thresh = dtc->thresh ?
- div64_u64(dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
+ div_u64((u64)dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
/*
* In order to avoid the stacked BDI deadlock we need
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 8dfcffa37094fef2c8cf8b602316766a86956d07
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024073032-uniquely-herring-53cb@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
8dfcffa37094 ("Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"")
9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8dfcffa37094fef2c8cf8b602316766a86956d07 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Fri, 21 Jun 2024 16:42:37 +0200
Subject: [PATCH] Revert "mm/writeback: fix possible divide-by-zero in
wb_dirty_limits(), again"
Patch series "mm: Avoid possible overflows in dirty throttling".
Dirty throttling logic assumes dirty limits in page units fit into
32-bits. This patch series makes sure this is true (see patch 2/2 for
more details).
This patch (of 2):
This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78.
The commit is broken in several ways. Firstly, the removed (u64) cast
from the multiplication will introduce a multiplication overflow on 32-bit
archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the
default settings with 4GB of RAM will trigger this). Secondly, the
div64_u64() is unnecessarily expensive on 32-bit archs. We have
div64_ul() in case we want to be safe & cheap. Thirdly, if dirty
thresholds are larger than 1<<32 pages, then dirty balancing is going to
blow up in many other spectacular ways anyway so trying to fix one
possible overflow is just moot.
Link: https://lkml.kernel.org/r/20240621144017.30993-1-jack@suse.cz
Link: https://lkml.kernel.org/r/20240621144246.11148-1-jack@suse.cz
Fixes: 9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
Signed-off-by: Jan Kara <jack(a)suse.cz>
Reviewed-By: Zach O'Keefe <zokeefe(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7168e25f88e5..c4aa6e84c20a 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1683,7 +1683,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
*/
dtc->wb_thresh = __wb_calc_thresh(dtc, dtc->thresh);
dtc->wb_bg_thresh = dtc->thresh ?
- div64_u64(dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
+ div_u64((u64)dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
/*
* In order to avoid the stacked BDI deadlock we need
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 8dfcffa37094fef2c8cf8b602316766a86956d07
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024073031-dandelion-revered-89bd@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
8dfcffa37094 ("Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"")
9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8dfcffa37094fef2c8cf8b602316766a86956d07 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Fri, 21 Jun 2024 16:42:37 +0200
Subject: [PATCH] Revert "mm/writeback: fix possible divide-by-zero in
wb_dirty_limits(), again"
Patch series "mm: Avoid possible overflows in dirty throttling".
Dirty throttling logic assumes dirty limits in page units fit into
32-bits. This patch series makes sure this is true (see patch 2/2 for
more details).
This patch (of 2):
This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78.
The commit is broken in several ways. Firstly, the removed (u64) cast
from the multiplication will introduce a multiplication overflow on 32-bit
archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the
default settings with 4GB of RAM will trigger this). Secondly, the
div64_u64() is unnecessarily expensive on 32-bit archs. We have
div64_ul() in case we want to be safe & cheap. Thirdly, if dirty
thresholds are larger than 1<<32 pages, then dirty balancing is going to
blow up in many other spectacular ways anyway so trying to fix one
possible overflow is just moot.
Link: https://lkml.kernel.org/r/20240621144017.30993-1-jack@suse.cz
Link: https://lkml.kernel.org/r/20240621144246.11148-1-jack@suse.cz
Fixes: 9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
Signed-off-by: Jan Kara <jack(a)suse.cz>
Reviewed-By: Zach O'Keefe <zokeefe(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7168e25f88e5..c4aa6e84c20a 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1683,7 +1683,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
*/
dtc->wb_thresh = __wb_calc_thresh(dtc, dtc->thresh);
dtc->wb_bg_thresh = dtc->thresh ?
- div64_u64(dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
+ div_u64((u64)dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
/*
* In order to avoid the stacked BDI deadlock we need
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 8dfcffa37094fef2c8cf8b602316766a86956d07
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024073030-affront-vigorous-240c@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
8dfcffa37094 ("Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"")
9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8dfcffa37094fef2c8cf8b602316766a86956d07 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Fri, 21 Jun 2024 16:42:37 +0200
Subject: [PATCH] Revert "mm/writeback: fix possible divide-by-zero in
wb_dirty_limits(), again"
Patch series "mm: Avoid possible overflows in dirty throttling".
Dirty throttling logic assumes dirty limits in page units fit into
32-bits. This patch series makes sure this is true (see patch 2/2 for
more details).
This patch (of 2):
This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78.
The commit is broken in several ways. Firstly, the removed (u64) cast
from the multiplication will introduce a multiplication overflow on 32-bit
archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the
default settings with 4GB of RAM will trigger this). Secondly, the
div64_u64() is unnecessarily expensive on 32-bit archs. We have
div64_ul() in case we want to be safe & cheap. Thirdly, if dirty
thresholds are larger than 1<<32 pages, then dirty balancing is going to
blow up in many other spectacular ways anyway so trying to fix one
possible overflow is just moot.
Link: https://lkml.kernel.org/r/20240621144017.30993-1-jack@suse.cz
Link: https://lkml.kernel.org/r/20240621144246.11148-1-jack@suse.cz
Fixes: 9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
Signed-off-by: Jan Kara <jack(a)suse.cz>
Reviewed-By: Zach O'Keefe <zokeefe(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7168e25f88e5..c4aa6e84c20a 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1683,7 +1683,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
*/
dtc->wb_thresh = __wb_calc_thresh(dtc, dtc->thresh);
dtc->wb_bg_thresh = dtc->thresh ?
- div64_u64(dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
+ div_u64((u64)dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
/*
* In order to avoid the stacked BDI deadlock we need
The patch below does not apply to the 6.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.10.y
git checkout FETCH_HEAD
git cherry-pick -x 8dfcffa37094fef2c8cf8b602316766a86956d07
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024073029-ungraded-buckskin-4be1@gregkh' --subject-prefix 'PATCH 6.10.y' HEAD^..
Possible dependencies:
8dfcffa37094 ("Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8dfcffa37094fef2c8cf8b602316766a86956d07 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Fri, 21 Jun 2024 16:42:37 +0200
Subject: [PATCH] Revert "mm/writeback: fix possible divide-by-zero in
wb_dirty_limits(), again"
Patch series "mm: Avoid possible overflows in dirty throttling".
Dirty throttling logic assumes dirty limits in page units fit into
32-bits. This patch series makes sure this is true (see patch 2/2 for
more details).
This patch (of 2):
This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78.
The commit is broken in several ways. Firstly, the removed (u64) cast
from the multiplication will introduce a multiplication overflow on 32-bit
archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the
default settings with 4GB of RAM will trigger this). Secondly, the
div64_u64() is unnecessarily expensive on 32-bit archs. We have
div64_ul() in case we want to be safe & cheap. Thirdly, if dirty
thresholds are larger than 1<<32 pages, then dirty balancing is going to
blow up in many other spectacular ways anyway so trying to fix one
possible overflow is just moot.
Link: https://lkml.kernel.org/r/20240621144017.30993-1-jack@suse.cz
Link: https://lkml.kernel.org/r/20240621144246.11148-1-jack@suse.cz
Fixes: 9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
Signed-off-by: Jan Kara <jack(a)suse.cz>
Reviewed-By: Zach O'Keefe <zokeefe(a)google.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7168e25f88e5..c4aa6e84c20a 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1683,7 +1683,7 @@ static inline void wb_dirty_limits(struct dirty_throttle_control *dtc)
*/
dtc->wb_thresh = __wb_calc_thresh(dtc, dtc->thresh);
dtc->wb_bg_thresh = dtc->thresh ?
- div64_u64(dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
+ div_u64((u64)dtc->wb_thresh * dtc->bg_thresh, dtc->thresh) : 0;
/*
* In order to avoid the stacked BDI deadlock we need
Connecting two 4k displays with display port through a lenovo usb-c dock (type 40AS) to a Lenovo P14s Gen 2 (type 21A0) results in no image on the connected displays.
The CPU in the Lenovo P14s is a 'AMD Ryzen 7 PRO 5850U with Radeon Graphics' and it has no discrete GPU.
I first noticed the issue with kernel version '6.10.0-arch1-2' provided by arch linux. With the previous kernel version '6.9.10.arch1-1' both connected displays worked normally. I reported the issue in the arch forums at https://bbs.archlinux.org/viewtopic.php?id=297999 and was guided to do a bisection to find the commit that caused the problem. Through testing I identified that the issue is not present in the latest kernel directly compiled from the trovalds/linux git repository.
With git bisect I identified 4df96ba66760345471a85ef7bb29e1cd4e956057 as the first bad commit and fa57924c76d995e87ca3533ec60d1d5e55769a27 as the first commit that fixed the problem again.
The initial commit only still shows an image on one of the connected 4k screens. I have not investigated further to find out at what point both displays stopped showing an image.
Best Regards,
Kevin
#regzbot introduced: 4df96ba66760345471a85ef7bb29e1cd4e956057