[PATCH AUTOSEL 4.19 1/3] tracing: Add NULL checks for buffer in ring_buffer_free_read_page()

[PATCH AUTOSEL 4.19 1/3] tracing: Add NULL checks for buffer in ring_buffer_free_read_page()

[Sasha Levin]

From: Jia-Ju Bai <baijiaju1990@gmail.com>

[ Upstream commit 3e4272b9954094907f16861199728f14002fcaf6 ]

In a previous commit 7433632c9ff6, buffer, buffer->buffers and
buffer->buffers[cpu] in ring_buffer_wake_waiters() can be NULL,
and thus the related checks are added.

However, in the same call stack, these variables are also used in
ring_buffer_free_read_page():

tracing_buffers_release()
  ring_buffer_wake_waiters(iter->array_buffer->buffer)
    cpu_buffer = buffer->buffers[cpu] -> Add checks by previous commit
  ring_buffer_free_read_page(iter->array_buffer->buffer)
    cpu_buffer = buffer->buffers[cpu] -> No check

Thus, to avod possible null-pointer derefernces, the related checks
should be added.

These results are reported by a static tool designed by myself.

Link: https://lkml.kernel.org/r/20230113125501.760324-1-baijiaju1990@gmail.com

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/trace/ring_buffer.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 5e5b0c067f611..bef3d01b8ff61 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -4685,11 +4685,16 @@ EXPORT_SYMBOL_GPL(ring_buffer_alloc_read_page);
  */
 void ring_buffer_free_read_page(struct ring_buffer *buffer, int cpu, void *data)
 {
-	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+	struct ring_buffer_per_cpu *cpu_buffer;
 	struct buffer_data_page *bpage = data;
 	struct page *page = virt_to_page(bpage);
 	unsigned long flags;
 
+	if (!buffer || !buffer->buffers || !buffer->buffers[cpu])
+		return;
+
+	cpu_buffer = buffer->buffers[cpu];
+
 	/* If the page is still in use someplace else, we can't reuse it */
 	if (page_ref_count(page) > 1)
 		goto out;
-- 
2.39.2

[PATCH AUTOSEL 4.19 2/3] efi: efivars: prevent double registration

[Sasha Levin]

From: Johan Hovold <johan+linaro@kernel.org>

[ Upstream commit 0217a40d7ba6e71d7f3422fbe89b436e8ee7ece7 ]

Add the missing sanity check to efivars_register() so that it is no
longer possible to override an already registered set of efivar ops
(without first deregistering them).

This can help debug initialisation ordering issues where drivers have so
far unknowingly been relying on overriding the generic ops.

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/firmware/efi/vars.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index e619ced030d52..462e88b9d2ba4 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -1195,19 +1195,28 @@ int efivars_register(struct efivars *efivars,
 		     const struct efivar_operations *ops,
 		     struct kobject *kobject)
 {
+	int rv;
+
 	if (down_interruptible(&efivars_lock))
 		return -EINTR;
 
+	if (__efivars) {
+		pr_warn("efivars already registered\n");
+		rv = -EBUSY;
+		goto out;
+	}
+
 	efivars->ops = ops;
 	efivars->kobject = kobject;
 
 	__efivars = efivars;
 
 	pr_info("Registered efivars operations\n");
-
+	rv = 0;
+out:
 	up(&efivars_lock);
 
-	return 0;
+	return rv;
 }
 EXPORT_SYMBOL_GPL(efivars_register);
 
-- 
2.39.2

Re: [PATCH AUTOSEL 4.19 2/3] efi: efivars: prevent double registration

[Ard Biesheuvel]

On Wed, 1 Mar 2023 at 17:30, Sasha Levin <sashal@kernel.org> wrote:
>
> From: Johan Hovold <johan+linaro@kernel.org>
>
> [ Upstream commit 0217a40d7ba6e71d7f3422fbe89b436e8ee7ece7 ]
>
> Add the missing sanity check to efivars_register() so that it is no
> longer possible to override an already registered set of efivar ops
> (without first deregistering them).
>
> This can help debug initialisation ordering issues where drivers have so
> far unknowingly been relying on overriding the generic ops.
>
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>

NAK this is not a bugfix.

> ---
>  drivers/firmware/efi/vars.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
> index e619ced030d52..462e88b9d2ba4 100644
> --- a/drivers/firmware/efi/vars.c
> +++ b/drivers/firmware/efi/vars.c
> @@ -1195,19 +1195,28 @@ int efivars_register(struct efivars *efivars,
>                      const struct efivar_operations *ops,
>                      struct kobject *kobject)
>  {
> +       int rv;
> +
>         if (down_interruptible(&efivars_lock))
>                 return -EINTR;
>
> +       if (__efivars) {
> +               pr_warn("efivars already registered\n");
> +               rv = -EBUSY;
> +               goto out;
> +       }
> +
>         efivars->ops = ops;
>         efivars->kobject = kobject;
>
>         __efivars = efivars;
>
>         pr_info("Registered efivars operations\n");
> -
> +       rv = 0;
> +out:
>         up(&efivars_lock);
>
> -       return 0;
> +       return rv;
>  }
>  EXPORT_SYMBOL_GPL(efivars_register);
>
> --
> 2.39.2
>

[PATCH AUTOSEL 4.19 3/3] firmware/efi sysfb_efi: Add quirk for Lenovo IdeaPad Duet 3

[Sasha Levin]

From: Darrell Kavanagh <darrell.kavanagh@gmail.com>

[ Upstream commit e1d447157f232c650e6f32c9fb89ff3d0207c69a ]

Another Lenovo convertable which reports a landscape resolution of
1920x1200 with a pitch of (1920 * 4) bytes, while the actual framebuffer
has a resolution of 1200x1920 with a pitch of (1200 * 4) bytes.

Signed-off-by: Darrell Kavanagh <darrell.kavanagh@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kernel/sysfb_efi.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/sysfb_efi.c b/arch/x86/kernel/sysfb_efi.c
index 897da526e40e6..dd8d7636c5420 100644
--- a/arch/x86/kernel/sysfb_efi.c
+++ b/arch/x86/kernel/sysfb_efi.c
@@ -265,6 +265,14 @@ static const struct dmi_system_id efifb_dmi_swap_width_height[] __initconst = {
 					"Lenovo ideapad D330-10IGM"),
 		},
 	},
+	{
+		/* Lenovo IdeaPad Duet 3 10IGL5 with 1200x1920 portrait screen */
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_VERSION,
+					"IdeaPad Duet 3 10IGL5"),
+		},
+	},
 	{},
 };
 
-- 
2.39.2