The patch below does not apply to the 4.9-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 bfe3911a91047557eb0e620f95a370aee6a248c7 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris(a)chris-wilson.co.uk>
Date: Fri, 5 Feb 2021 22:00:12 +0000
Subject: [PATCH] kcmp: Support selection of SYS_kcmp without
CHECKPOINT_RESTORE
Userspace has discovered the functionality offered by SYS_kcmp and has
started to depend upon it. In particular, Mesa uses SYS_kcmp for
os_same_file_description() in order to identify when two fd (e.g. device
or dmabuf) point to the same struct file. Since they depend on it for
core functionality, lift SYS_kcmp out of the non-default
CONFIG_CHECKPOINT_RESTORE into the selectable syscall category.
Rasmus Villemoes also pointed out that systemd uses SYS_kcmp to
deduplicate the per-service file descriptor store.
Note that some distributions such as Ubuntu are already enabling
CHECKPOINT_RESTORE in their configs and so, by extension, SYS_kcmp.
References: https://gitlab.freedesktop.org/drm/intel/-/issues/3046
Signed-off-by: Chris Wilson <chris(a)chris-wilson.co.uk>
Cc: Kees Cook <keescook(a)chromium.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Will Drewry <wad(a)chromium.org>
Cc: Andrew Morton <akpm(a)linux-foundation.org>
Cc: Dave Airlie <airlied(a)gmail.com>
Cc: Daniel Vetter <daniel(a)ffwll.ch>
Cc: Lucas Stach <l.stach(a)pengutronix.de>
Cc: Rasmus Villemoes <linux(a)rasmusvillemoes.dk>
Cc: Cyrill Gorcunov <gorcunov(a)gmail.com>
Cc: stable(a)vger.kernel.org
Acked-by: Daniel Vetter <daniel.vetter(a)ffwll.ch> # DRM depends on kcmp
Acked-by: Rasmus Villemoes <linux(a)rasmusvillemoes.dk> # systemd uses kcmp
Reviewed-by: Cyrill Gorcunov <gorcunov(a)gmail.com>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Thomas Zimmermann <tzimmermann(a)suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter(a)ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@c…
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 0973f408d75f..af6c6d214d91 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -15,6 +15,9 @@ menuconfig DRM
select I2C_ALGOBIT
select DMA_SHARED_BUFFER
select SYNC_FILE
+# gallium uses SYS_kcmp for os_same_file_description() to de-duplicate
+# device and dmabuf fd. Let's make sure that is available for our userspace.
+ select KCMP
help
Kernel-level support for the Direct Rendering Infrastructure (DRI)
introduced in XFree86 4.0. If you say Y here, you need to select
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index a829af074eb5..3196474cbe24 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -979,7 +979,7 @@ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd)
return epir;
}
-#ifdef CONFIG_CHECKPOINT_RESTORE
+#ifdef CONFIG_KCMP
static struct epitem *ep_find_tfd(struct eventpoll *ep, int tfd, unsigned long toff)
{
struct rb_node *rbp;
@@ -1021,7 +1021,7 @@ struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd,
return file_raw;
}
-#endif /* CONFIG_CHECKPOINT_RESTORE */
+#endif /* CONFIG_KCMP */
/**
* Adds a new entry to the tail of the list in a lockless way, i.e.
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
index 0350393465d4..593322c946e6 100644
--- a/include/linux/eventpoll.h
+++ b/include/linux/eventpoll.h
@@ -18,7 +18,7 @@ struct file;
#ifdef CONFIG_EPOLL
-#ifdef CONFIG_CHECKPOINT_RESTORE
+#ifdef CONFIG_KCMP
struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff);
#endif
diff --git a/init/Kconfig b/init/Kconfig
index 29ad68325028..b7d3c6a12196 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1193,6 +1193,7 @@ endif # NAMESPACES
config CHECKPOINT_RESTORE
bool "Checkpoint/restore support"
select PROC_CHILDREN
+ select KCMP
default n
help
Enables additional kernel features in a sake of checkpoint/restore.
@@ -1736,6 +1737,16 @@ config ARCH_HAS_MEMBARRIER_CALLBACKS
config ARCH_HAS_MEMBARRIER_SYNC_CORE
bool
+config KCMP
+ bool "Enable kcmp() system call" if EXPERT
+ help
+ Enable the kernel resource comparison system call. It provides
+ user-space with the ability to compare two processes to see if they
+ share a common resource, such as a file descriptor or even virtual
+ memory space.
+
+ If unsure, say N.
+
config RSEQ
bool "Enable rseq() system call" if EXPERT
default y
diff --git a/kernel/Makefile b/kernel/Makefile
index aa7368c7eabf..320f1f3941b7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -51,7 +51,7 @@ obj-y += livepatch/
obj-y += dma/
obj-y += entry/
-obj-$(CONFIG_CHECKPOINT_RESTORE) += kcmp.o
+obj-$(CONFIG_KCMP) += kcmp.o
obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_PROFILING) += profile.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 26c72f2b61b1..1b6c7d33c4ff 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -315,7 +315,7 @@ TEST(kcmp)
ret = __filecmp(getpid(), getpid(), 1, 1);
EXPECT_EQ(ret, 0);
if (ret != 0 && errno == ENOSYS)
- SKIP(return, "Kernel does not support kcmp() (missing CONFIG_CHECKPOINT_RESTORE?)");
+ SKIP(return, "Kernel does not support kcmp() (missing CONFIG_KCMP?)");
}
TEST(mode_strict_support)
The patch below does not apply to the 4.14-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 bfe3911a91047557eb0e620f95a370aee6a248c7 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris(a)chris-wilson.co.uk>
Date: Fri, 5 Feb 2021 22:00:12 +0000
Subject: [PATCH] kcmp: Support selection of SYS_kcmp without
CHECKPOINT_RESTORE
Userspace has discovered the functionality offered by SYS_kcmp and has
started to depend upon it. In particular, Mesa uses SYS_kcmp for
os_same_file_description() in order to identify when two fd (e.g. device
or dmabuf) point to the same struct file. Since they depend on it for
core functionality, lift SYS_kcmp out of the non-default
CONFIG_CHECKPOINT_RESTORE into the selectable syscall category.
Rasmus Villemoes also pointed out that systemd uses SYS_kcmp to
deduplicate the per-service file descriptor store.
Note that some distributions such as Ubuntu are already enabling
CHECKPOINT_RESTORE in their configs and so, by extension, SYS_kcmp.
References: https://gitlab.freedesktop.org/drm/intel/-/issues/3046
Signed-off-by: Chris Wilson <chris(a)chris-wilson.co.uk>
Cc: Kees Cook <keescook(a)chromium.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Will Drewry <wad(a)chromium.org>
Cc: Andrew Morton <akpm(a)linux-foundation.org>
Cc: Dave Airlie <airlied(a)gmail.com>
Cc: Daniel Vetter <daniel(a)ffwll.ch>
Cc: Lucas Stach <l.stach(a)pengutronix.de>
Cc: Rasmus Villemoes <linux(a)rasmusvillemoes.dk>
Cc: Cyrill Gorcunov <gorcunov(a)gmail.com>
Cc: stable(a)vger.kernel.org
Acked-by: Daniel Vetter <daniel.vetter(a)ffwll.ch> # DRM depends on kcmp
Acked-by: Rasmus Villemoes <linux(a)rasmusvillemoes.dk> # systemd uses kcmp
Reviewed-by: Cyrill Gorcunov <gorcunov(a)gmail.com>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Thomas Zimmermann <tzimmermann(a)suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter(a)ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@c…
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 0973f408d75f..af6c6d214d91 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -15,6 +15,9 @@ menuconfig DRM
select I2C_ALGOBIT
select DMA_SHARED_BUFFER
select SYNC_FILE
+# gallium uses SYS_kcmp for os_same_file_description() to de-duplicate
+# device and dmabuf fd. Let's make sure that is available for our userspace.
+ select KCMP
help
Kernel-level support for the Direct Rendering Infrastructure (DRI)
introduced in XFree86 4.0. If you say Y here, you need to select
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index a829af074eb5..3196474cbe24 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -979,7 +979,7 @@ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd)
return epir;
}
-#ifdef CONFIG_CHECKPOINT_RESTORE
+#ifdef CONFIG_KCMP
static struct epitem *ep_find_tfd(struct eventpoll *ep, int tfd, unsigned long toff)
{
struct rb_node *rbp;
@@ -1021,7 +1021,7 @@ struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd,
return file_raw;
}
-#endif /* CONFIG_CHECKPOINT_RESTORE */
+#endif /* CONFIG_KCMP */
/**
* Adds a new entry to the tail of the list in a lockless way, i.e.
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
index 0350393465d4..593322c946e6 100644
--- a/include/linux/eventpoll.h
+++ b/include/linux/eventpoll.h
@@ -18,7 +18,7 @@ struct file;
#ifdef CONFIG_EPOLL
-#ifdef CONFIG_CHECKPOINT_RESTORE
+#ifdef CONFIG_KCMP
struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff);
#endif
diff --git a/init/Kconfig b/init/Kconfig
index 29ad68325028..b7d3c6a12196 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1193,6 +1193,7 @@ endif # NAMESPACES
config CHECKPOINT_RESTORE
bool "Checkpoint/restore support"
select PROC_CHILDREN
+ select KCMP
default n
help
Enables additional kernel features in a sake of checkpoint/restore.
@@ -1736,6 +1737,16 @@ config ARCH_HAS_MEMBARRIER_CALLBACKS
config ARCH_HAS_MEMBARRIER_SYNC_CORE
bool
+config KCMP
+ bool "Enable kcmp() system call" if EXPERT
+ help
+ Enable the kernel resource comparison system call. It provides
+ user-space with the ability to compare two processes to see if they
+ share a common resource, such as a file descriptor or even virtual
+ memory space.
+
+ If unsure, say N.
+
config RSEQ
bool "Enable rseq() system call" if EXPERT
default y
diff --git a/kernel/Makefile b/kernel/Makefile
index aa7368c7eabf..320f1f3941b7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -51,7 +51,7 @@ obj-y += livepatch/
obj-y += dma/
obj-y += entry/
-obj-$(CONFIG_CHECKPOINT_RESTORE) += kcmp.o
+obj-$(CONFIG_KCMP) += kcmp.o
obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_PROFILING) += profile.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 26c72f2b61b1..1b6c7d33c4ff 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -315,7 +315,7 @@ TEST(kcmp)
ret = __filecmp(getpid(), getpid(), 1, 1);
EXPECT_EQ(ret, 0);
if (ret != 0 && errno == ENOSYS)
- SKIP(return, "Kernel does not support kcmp() (missing CONFIG_CHECKPOINT_RESTORE?)");
+ SKIP(return, "Kernel does not support kcmp() (missing CONFIG_KCMP?)");
}
TEST(mode_strict_support)
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 bfe3911a91047557eb0e620f95a370aee6a248c7 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris(a)chris-wilson.co.uk>
Date: Fri, 5 Feb 2021 22:00:12 +0000
Subject: [PATCH] kcmp: Support selection of SYS_kcmp without
CHECKPOINT_RESTORE
Userspace has discovered the functionality offered by SYS_kcmp and has
started to depend upon it. In particular, Mesa uses SYS_kcmp for
os_same_file_description() in order to identify when two fd (e.g. device
or dmabuf) point to the same struct file. Since they depend on it for
core functionality, lift SYS_kcmp out of the non-default
CONFIG_CHECKPOINT_RESTORE into the selectable syscall category.
Rasmus Villemoes also pointed out that systemd uses SYS_kcmp to
deduplicate the per-service file descriptor store.
Note that some distributions such as Ubuntu are already enabling
CHECKPOINT_RESTORE in their configs and so, by extension, SYS_kcmp.
References: https://gitlab.freedesktop.org/drm/intel/-/issues/3046
Signed-off-by: Chris Wilson <chris(a)chris-wilson.co.uk>
Cc: Kees Cook <keescook(a)chromium.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Will Drewry <wad(a)chromium.org>
Cc: Andrew Morton <akpm(a)linux-foundation.org>
Cc: Dave Airlie <airlied(a)gmail.com>
Cc: Daniel Vetter <daniel(a)ffwll.ch>
Cc: Lucas Stach <l.stach(a)pengutronix.de>
Cc: Rasmus Villemoes <linux(a)rasmusvillemoes.dk>
Cc: Cyrill Gorcunov <gorcunov(a)gmail.com>
Cc: stable(a)vger.kernel.org
Acked-by: Daniel Vetter <daniel.vetter(a)ffwll.ch> # DRM depends on kcmp
Acked-by: Rasmus Villemoes <linux(a)rasmusvillemoes.dk> # systemd uses kcmp
Reviewed-by: Cyrill Gorcunov <gorcunov(a)gmail.com>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Thomas Zimmermann <tzimmermann(a)suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter(a)ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@c…
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 0973f408d75f..af6c6d214d91 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -15,6 +15,9 @@ menuconfig DRM
select I2C_ALGOBIT
select DMA_SHARED_BUFFER
select SYNC_FILE
+# gallium uses SYS_kcmp for os_same_file_description() to de-duplicate
+# device and dmabuf fd. Let's make sure that is available for our userspace.
+ select KCMP
help
Kernel-level support for the Direct Rendering Infrastructure (DRI)
introduced in XFree86 4.0. If you say Y here, you need to select
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index a829af074eb5..3196474cbe24 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -979,7 +979,7 @@ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd)
return epir;
}
-#ifdef CONFIG_CHECKPOINT_RESTORE
+#ifdef CONFIG_KCMP
static struct epitem *ep_find_tfd(struct eventpoll *ep, int tfd, unsigned long toff)
{
struct rb_node *rbp;
@@ -1021,7 +1021,7 @@ struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd,
return file_raw;
}
-#endif /* CONFIG_CHECKPOINT_RESTORE */
+#endif /* CONFIG_KCMP */
/**
* Adds a new entry to the tail of the list in a lockless way, i.e.
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
index 0350393465d4..593322c946e6 100644
--- a/include/linux/eventpoll.h
+++ b/include/linux/eventpoll.h
@@ -18,7 +18,7 @@ struct file;
#ifdef CONFIG_EPOLL
-#ifdef CONFIG_CHECKPOINT_RESTORE
+#ifdef CONFIG_KCMP
struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff);
#endif
diff --git a/init/Kconfig b/init/Kconfig
index 29ad68325028..b7d3c6a12196 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1193,6 +1193,7 @@ endif # NAMESPACES
config CHECKPOINT_RESTORE
bool "Checkpoint/restore support"
select PROC_CHILDREN
+ select KCMP
default n
help
Enables additional kernel features in a sake of checkpoint/restore.
@@ -1736,6 +1737,16 @@ config ARCH_HAS_MEMBARRIER_CALLBACKS
config ARCH_HAS_MEMBARRIER_SYNC_CORE
bool
+config KCMP
+ bool "Enable kcmp() system call" if EXPERT
+ help
+ Enable the kernel resource comparison system call. It provides
+ user-space with the ability to compare two processes to see if they
+ share a common resource, such as a file descriptor or even virtual
+ memory space.
+
+ If unsure, say N.
+
config RSEQ
bool "Enable rseq() system call" if EXPERT
default y
diff --git a/kernel/Makefile b/kernel/Makefile
index aa7368c7eabf..320f1f3941b7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -51,7 +51,7 @@ obj-y += livepatch/
obj-y += dma/
obj-y += entry/
-obj-$(CONFIG_CHECKPOINT_RESTORE) += kcmp.o
+obj-$(CONFIG_KCMP) += kcmp.o
obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_PROFILING) += profile.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 26c72f2b61b1..1b6c7d33c4ff 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -315,7 +315,7 @@ TEST(kcmp)
ret = __filecmp(getpid(), getpid(), 1, 1);
EXPECT_EQ(ret, 0);
if (ret != 0 && errno == ENOSYS)
- SKIP(return, "Kernel does not support kcmp() (missing CONFIG_CHECKPOINT_RESTORE?)");
+ SKIP(return, "Kernel does not support kcmp() (missing CONFIG_KCMP?)");
}
TEST(mode_strict_support)
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 bfe3911a91047557eb0e620f95a370aee6a248c7 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris(a)chris-wilson.co.uk>
Date: Fri, 5 Feb 2021 22:00:12 +0000
Subject: [PATCH] kcmp: Support selection of SYS_kcmp without
CHECKPOINT_RESTORE
Userspace has discovered the functionality offered by SYS_kcmp and has
started to depend upon it. In particular, Mesa uses SYS_kcmp for
os_same_file_description() in order to identify when two fd (e.g. device
or dmabuf) point to the same struct file. Since they depend on it for
core functionality, lift SYS_kcmp out of the non-default
CONFIG_CHECKPOINT_RESTORE into the selectable syscall category.
Rasmus Villemoes also pointed out that systemd uses SYS_kcmp to
deduplicate the per-service file descriptor store.
Note that some distributions such as Ubuntu are already enabling
CHECKPOINT_RESTORE in their configs and so, by extension, SYS_kcmp.
References: https://gitlab.freedesktop.org/drm/intel/-/issues/3046
Signed-off-by: Chris Wilson <chris(a)chris-wilson.co.uk>
Cc: Kees Cook <keescook(a)chromium.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Will Drewry <wad(a)chromium.org>
Cc: Andrew Morton <akpm(a)linux-foundation.org>
Cc: Dave Airlie <airlied(a)gmail.com>
Cc: Daniel Vetter <daniel(a)ffwll.ch>
Cc: Lucas Stach <l.stach(a)pengutronix.de>
Cc: Rasmus Villemoes <linux(a)rasmusvillemoes.dk>
Cc: Cyrill Gorcunov <gorcunov(a)gmail.com>
Cc: stable(a)vger.kernel.org
Acked-by: Daniel Vetter <daniel.vetter(a)ffwll.ch> # DRM depends on kcmp
Acked-by: Rasmus Villemoes <linux(a)rasmusvillemoes.dk> # systemd uses kcmp
Reviewed-by: Cyrill Gorcunov <gorcunov(a)gmail.com>
Reviewed-by: Kees Cook <keescook(a)chromium.org>
Acked-by: Thomas Zimmermann <tzimmermann(a)suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter(a)ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@c…
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 0973f408d75f..af6c6d214d91 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -15,6 +15,9 @@ menuconfig DRM
select I2C_ALGOBIT
select DMA_SHARED_BUFFER
select SYNC_FILE
+# gallium uses SYS_kcmp for os_same_file_description() to de-duplicate
+# device and dmabuf fd. Let's make sure that is available for our userspace.
+ select KCMP
help
Kernel-level support for the Direct Rendering Infrastructure (DRI)
introduced in XFree86 4.0. If you say Y here, you need to select
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index a829af074eb5..3196474cbe24 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -979,7 +979,7 @@ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd)
return epir;
}
-#ifdef CONFIG_CHECKPOINT_RESTORE
+#ifdef CONFIG_KCMP
static struct epitem *ep_find_tfd(struct eventpoll *ep, int tfd, unsigned long toff)
{
struct rb_node *rbp;
@@ -1021,7 +1021,7 @@ struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd,
return file_raw;
}
-#endif /* CONFIG_CHECKPOINT_RESTORE */
+#endif /* CONFIG_KCMP */
/**
* Adds a new entry to the tail of the list in a lockless way, i.e.
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
index 0350393465d4..593322c946e6 100644
--- a/include/linux/eventpoll.h
+++ b/include/linux/eventpoll.h
@@ -18,7 +18,7 @@ struct file;
#ifdef CONFIG_EPOLL
-#ifdef CONFIG_CHECKPOINT_RESTORE
+#ifdef CONFIG_KCMP
struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long toff);
#endif
diff --git a/init/Kconfig b/init/Kconfig
index 29ad68325028..b7d3c6a12196 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1193,6 +1193,7 @@ endif # NAMESPACES
config CHECKPOINT_RESTORE
bool "Checkpoint/restore support"
select PROC_CHILDREN
+ select KCMP
default n
help
Enables additional kernel features in a sake of checkpoint/restore.
@@ -1736,6 +1737,16 @@ config ARCH_HAS_MEMBARRIER_CALLBACKS
config ARCH_HAS_MEMBARRIER_SYNC_CORE
bool
+config KCMP
+ bool "Enable kcmp() system call" if EXPERT
+ help
+ Enable the kernel resource comparison system call. It provides
+ user-space with the ability to compare two processes to see if they
+ share a common resource, such as a file descriptor or even virtual
+ memory space.
+
+ If unsure, say N.
+
config RSEQ
bool "Enable rseq() system call" if EXPERT
default y
diff --git a/kernel/Makefile b/kernel/Makefile
index aa7368c7eabf..320f1f3941b7 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -51,7 +51,7 @@ obj-y += livepatch/
obj-y += dma/
obj-y += entry/
-obj-$(CONFIG_CHECKPOINT_RESTORE) += kcmp.o
+obj-$(CONFIG_KCMP) += kcmp.o
obj-$(CONFIG_FREEZER) += freezer.o
obj-$(CONFIG_PROFILING) += profile.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 26c72f2b61b1..1b6c7d33c4ff 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -315,7 +315,7 @@ TEST(kcmp)
ret = __filecmp(getpid(), getpid(), 1, 1);
EXPECT_EQ(ret, 0);
if (ret != 0 && errno == ENOSYS)
- SKIP(return, "Kernel does not support kcmp() (missing CONFIG_CHECKPOINT_RESTORE?)");
+ SKIP(return, "Kernel does not support kcmp() (missing CONFIG_KCMP?)");
}
TEST(mode_strict_support)
On Thu 2021-02-11 18:37:52, John Ogness wrote:
> If message sizes average larger than expected (more than 32
> characters), the data_ring will wrap before the desc_ring. Once the
> data_ring wraps, it will start invalidating descriptors. These
> invalid descriptors hang around until they are eventually recycled
> when the desc_ring wraps. Readers do not care about invalid
> descriptors, but they still need to iterate past them. If the
> average message size is much larger than 32 characters, then there
> will be many invalid descriptors preceding the valid descriptors.
>
> The function prb_first_valid_seq() always begins at the oldest
> descriptor and searches for the first valid descriptor. This can
> be rather expensive for the above scenario. And, in fact, because
> of its heavy usage in /dev/kmsg, there have been reports of long
> delays and even RCU stalls.
>
> For code that does not need to search from the oldest record,
> replace prb_first_valid_seq() usage with prb_read_valid_*()
> functions, which provide a start sequence number to search from.
>
> Fixes: 896fbe20b4e2333fb55 ("printk: use the lockless ringbuffer")
> Reported-by: kernel test robot <oliver.sang(a)intel.com>
> Reported-by: J. Avila <elavila(a)google.com>
> Signed-off-by: John Ogness <john.ogness(a)linutronix.de>
Could you please push this fix into the stable releases
based on 5.10 and 5.11, please?
The patch fixes a visible performance regression. It has
landed in the mainline as the commit
13791c80b0cdf54d92fc542 ("printk: avoid prb_first_valid_seq() where
possible").
It should apply cleanly.
Best Regards,
Petr
This is backport of 3642eb21256a ("powerpc/32: Preserve cr1 in
exception prolog stack check to fix build error") for kernel 5.10
It fixes the build failure on v5.10 reported by kernel test robot
and by David Michael.
This fix is not in Linux tree yet, it is in next branch in powerpc tree.
(cherry picked from commit 3642eb21256a317ac14e9ed560242c6d20cf06d9)
THREAD_ALIGN_SHIFT = THREAD_SHIFT + 1 = PAGE_SHIFT + 1
Maximum PAGE_SHIFT is 18 for 256k pages so
THREAD_ALIGN_SHIFT is 19 at the maximum.
No need to clobber cr1, it can be preserved when moving r1
into CR when we check stack overflow.
This reduces the number of instructions in Machine Check Exception
prolog and fixes a build failure reported by the kernel test robot
on v5.10 stable when building with RTAS + VMAP_STACK + KVM. That
build failure is due to too many instructions in the prolog hence
not fitting between 0x200 and 0x300. Allthough the problem doesn't
show up in mainline, it is still worth the change.
Fixes: 98bf2d3f4970 ("powerpc/32s: Fix RTAS machine check with VMAP stack")
Cc: stable(a)vger.kernel.org
Reported-by: kernel test robot <lkp(a)intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy(a)csgroup.eu>
Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au>
Link: https://lore.kernel.org/r/5ae4d545e3ac58e133d2599e0deb88843cb494fc.16127686…
---
arch/powerpc/kernel/head_32.h | 2 +-
arch/powerpc/kernel/head_book3s_32.S | 6 ------
2 files changed, 1 insertion(+), 7 deletions(-)
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index c88e66adecb5..fef0b34a77c9 100644
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -56,7 +56,7 @@
1:
tophys_novmstack r11, r11
#ifdef CONFIG_VMAP_STACK
- mtcrf 0x7f, r1
+ mtcrf 0x3f, r1
bt 32 - THREAD_ALIGN_SHIFT, stack_overflow
#endif
.endm
diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index d66da35f2e8d..2729d8fa6e77 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -280,12 +280,6 @@ MachineCheck:
7: EXCEPTION_PROLOG_2
addi r3,r1,STACK_FRAME_OVERHEAD
#ifdef CONFIG_PPC_CHRP
-#ifdef CONFIG_VMAP_STACK
- mfspr r4, SPRN_SPRG_THREAD
- tovirt(r4, r4)
- lwz r4, RTAS_SP(r4)
- cmpwi cr1, r4, 0
-#endif
beq cr1, machine_check_tramp
twi 31, 0, 0
#else
--
2.25.0
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 c0b15c25d25171db4b70cc0b7dbc1130ee94017d Mon Sep 17 00:00:00 2001
From: Suzuki K Poulose <suzuki.poulose(a)arm.com>
Date: Wed, 3 Feb 2021 23:00:57 +0000
Subject: [PATCH] arm64: Extend workaround for erratum 1024718 to all versions
of Cortex-A55
The erratum 1024718 affects Cortex-A55 r0p0 to r2p0. However
we apply the work around for r0p0 - r1p0. Unfortunately this
won't be fixed for the future revisions for the CPU. Thus
extend the work around for all versions of A55, to cover
for r2p0 and any future revisions.
Cc: stable(a)vger.kernel.org
Cc: Catalin Marinas <catalin.marinas(a)arm.com>
Cc: Will Deacon <will(a)kernel.org>
Cc: James Morse <james.morse(a)arm.com>
Cc: Kunihiko Hayashi <hayashi.kunihiko(a)socionext.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose(a)arm.com>
Link: https://lore.kernel.org/r/20210203230057.3961239-1-suzuki.poulose@arm.com
[will: Update Kconfig help text]
Signed-off-by: Will Deacon <will(a)kernel.org>
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f39568b28ec1..3dfb25afa616 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -522,7 +522,7 @@ config ARM64_ERRATUM_1024718
help
This option adds a workaround for ARM Cortex-A55 Erratum 1024718.
- Affected Cortex-A55 cores (r0p0, r0p1, r1p0) could cause incorrect
+ Affected Cortex-A55 cores (all revisions) could cause incorrect
update of the hardware dirty bit when the DBM/AP bits are updated
without a break-before-make. The workaround is to disable the usage
of hardware DBM locally on the affected cores. CPUs not affected by
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index e99eddec0a46..db400ca77427 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1455,7 +1455,7 @@ static bool cpu_has_broken_dbm(void)
/* List of CPUs which have broken DBM support. */
static const struct midr_range cpus[] = {
#ifdef CONFIG_ARM64_ERRATUM_1024718
- MIDR_RANGE(MIDR_CORTEX_A55, 0, 0, 1, 0), // A55 r0p0 -r1p0
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A55),
/* Kryo4xx Silver (rdpe => r1p0) */
MIDR_REV(MIDR_QCOM_KRYO_4XX_SILVER, 0xd, 0xe),
#endif
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 7018c897c2f243d4b5f1b94bc6b4831a7eab80fb Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams(a)intel.com>
Date: Mon, 1 Feb 2021 16:20:40 -0800
Subject: [PATCH] libnvdimm/dimm: Avoid race between probe and
available_slots_show()
Richard reports that the following test:
(while true; do
cat /sys/bus/nd/devices/nmem*/available_slots 2>&1 > /dev/null
done) &
while true; do
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/bind
done
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/unbind
done
done
...fails with a crash signature like:
divide error: 0000 [#1] SMP KASAN PTI
RIP: 0010:nd_label_nfree+0x134/0x1a0 [libnvdimm]
[..]
Call Trace:
available_slots_show+0x4e/0x120 [libnvdimm]
dev_attr_show+0x42/0x80
? memset+0x20/0x40
sysfs_kf_seq_show+0x218/0x410
The root cause is that available_slots_show() consults driver-data, but
fails to synchronize against device-unbind setting up a TOCTOU race to
access uninitialized memory.
Validate driver-data under the device-lock.
Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver infrastructure")
Cc: <stable(a)vger.kernel.org>
Cc: Vishal Verma <vishal.l.verma(a)intel.com>
Cc: Dave Jiang <dave.jiang(a)intel.com>
Cc: Ira Weiny <ira.weiny(a)intel.com>
Cc: Coly Li <colyli(a)suse.com>
Reported-by: Richard Palethorpe <rpalethorpe(a)suse.com>
Acked-by: Richard Palethorpe <rpalethorpe(a)suse.com>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index b59032e0859b..9d208570d059 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -335,16 +335,16 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RO(state);
-static ssize_t available_slots_show(struct device *dev,
- struct device_attribute *attr, char *buf)
+static ssize_t __available_slots_show(struct nvdimm_drvdata *ndd, char *buf)
{
- struct nvdimm_drvdata *ndd = dev_get_drvdata(dev);
+ struct device *dev;
ssize_t rc;
u32 nfree;
if (!ndd)
return -ENXIO;
+ dev = ndd->dev;
nvdimm_bus_lock(dev);
nfree = nd_label_nfree(ndd);
if (nfree - 1 > nfree) {
@@ -356,6 +356,18 @@ static ssize_t available_slots_show(struct device *dev,
nvdimm_bus_unlock(dev);
return rc;
}
+
+static ssize_t available_slots_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ ssize_t rc;
+
+ nd_device_lock(dev);
+ rc = __available_slots_show(dev_get_drvdata(dev), buf);
+ nd_device_unlock(dev);
+
+ return rc;
+}
static DEVICE_ATTR_RO(available_slots);
__weak ssize_t security_show(struct device *dev,