[PATCH][v2] Drivers: hv: Change flag to write log level in panic msg to false

Subsystems: hyper-v/azure core and drivers, the rest

STALE2255d LANDED

Landed in mainline as 77b48bea2fee on 2020-06-29.

6 messages, 4 authors, 2020-07-06 · open the first message on its own page

[PATCH][v2] Drivers: hv: Change flag to write log level in panic msg to false

From: Joseph Salisbury <hidden>
Date: 2020-06-26 22:28:18 

When the kernel panics, one page of kmsg data may be collected and sent to
Hyper-V to aid in diagnosing the failure.  The collected kmsg data typically
 contains 50 to 100 lines, each of which has a log level prefix that isn't
very useful from a diagnostic standpoint.  So tell kmsg_dump_get_buffer()
to not include the log level, enabling more information that *is* useful to
fit in the page.

Requesting in stable kernels, since many kernels running in production are
stable releases.

Cc: stable@vger.kernel.org
Signed-off-by: Joseph Salisbury <redacted>
---
 drivers/hv/vmbus_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 9147ee9d5f7d..d69f4efa3719 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1368,7 +1368,7 @@ static void hv_kmsg_dump(struct kmsg_dumper *dumper,
 	 * Write dump contents to the page. No need to synchronize; panic should
 	 * be single-threaded.
 	 */
-	kmsg_dump_get_buffer(dumper, true, hv_panic_page, HV_HYP_PAGE_SIZE,
+	kmsg_dump_get_buffer(dumper, false, hv_panic_page, HV_HYP_PAGE_SIZE,
 			     &bytes_written);
 	if (bytes_written)
 		hyperv_report_panic_msg(panic_pa, bytes_written);
-- 
2.17.1

Re: [PATCH][v2] Drivers: hv: Change flag to write log level in panic msg to false

From: Wei Liu <wei.liu@kernel.org>
Date: 2020-06-29 20:58:11 

On Fri, Jun 26, 2020 at 03:28:17PM -0700, Joseph Salisbury wrote:
When the kernel panics, one page of kmsg data may be collected and sent to
Hyper-V to aid in diagnosing the failure.  The collected kmsg data typically
 contains 50 to 100 lines, each of which has a log level prefix that isn't
very useful from a diagnostic standpoint.  So tell kmsg_dump_get_buffer()
to not include the log level, enabling more information that *is* useful to
fit in the page.

Requesting in stable kernels, since many kernels running in production are
stable releases.

Cc: stable@vger.kernel.org
Signed-off-by: Joseph Salisbury <redacted>
Applied to hyperv-fixes with Michael's review from v1. Thanks.
quoted hunk
---
 drivers/hv/vmbus_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 9147ee9d5f7d..d69f4efa3719 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1368,7 +1368,7 @@ static void hv_kmsg_dump(struct kmsg_dumper *dumper,
 	 * Write dump contents to the page. No need to synchronize; panic should
 	 * be single-threaded.
 	 */
-	kmsg_dump_get_buffer(dumper, true, hv_panic_page, HV_HYP_PAGE_SIZE,
+	kmsg_dump_get_buffer(dumper, false, hv_panic_page, HV_HYP_PAGE_SIZE,
 			     &bytes_written);
 	if (bytes_written)
 		hyperv_report_panic_msg(panic_pa, bytes_written);
-- 
2.17.1

Re: [PATCH][v2] Drivers: hv: Change flag to write log level in panic msg to false

From: Sasha Levin <sashal@kernel.org>
Date: 2020-07-01 19:33:32 

Hi

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all

The bot has tested the following trees: v5.7.6, v5.4.49, v4.19.130, v4.14.186, v4.9.228, v4.4.228.

v5.7.6: Build OK!
v5.4.49: Failed to apply! Possible dependencies:
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")

v4.19.130: Failed to apply! Possible dependencies:
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")

v4.14.186: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
    7ed4325a44ea5 ("Drivers: hv: vmbus: Make panic reporting to be more useful")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
    8afc06dd75c06 ("Drivers: hv: vmbus: Fix the issue with freeing up hv_ctl_table_hdr")
    ddcaf3ca4c3c8 ("Drivers: hv: vmus: Fix the check for return value from kmsg get dump buffer")

v4.9.228: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common code")
    73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
    76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
    8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
    d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")

v4.4.228: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    619848bd07434 ("drivers:hv: Export a function that maps Linux CPU num onto Hyper-V proc num")
    6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common code")
    73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
    75ff3a8a9168d ("Drivers: hv: vmbus: avoid wait_for_completion() on crash")
    76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
    8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
    a108393dbf764 ("drivers:hv: Export the API to invoke a hypercall on Hyper-V")
    d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?

-- 
Thanks
Sasha

Re: [PATCH][v2] Drivers: hv: Change flag to write log level in panic msg to false

From: Wei Liu <wei.liu@kernel.org>
Date: 2020-07-06 10:56:11 

On Wed, Jul 01, 2020 at 07:33:25PM +0000, Sasha Levin wrote:
Hi

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all

The bot has tested the following trees: v5.7.6, v5.4.49, v4.19.130, v4.14.186, v4.9.228, v4.4.228.

v5.7.6: Build OK!
v5.4.49: Failed to apply! Possible dependencies:
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
Unrelated, shouldn't be backported.

v4.19.130: Failed to apply! Possible dependencies:
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
Unrelated, shouldn't be backported.

v4.14.186: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
    7ed4325a44ea5 ("Drivers: hv: vmbus: Make panic reporting to be more useful")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
    8afc06dd75c06 ("Drivers: hv: vmbus: Fix the issue with freeing up hv_ctl_table_hdr")
    ddcaf3ca4c3c8 ("Drivers: hv: vmus: Fix the check for return value from kmsg get dump buffer")

v4.9.228: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common code")
    73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
    76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
    8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
    d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")

v4.4.228: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    619848bd07434 ("drivers:hv: Export a function that maps Linux CPU num onto Hyper-V proc num")
    6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common code")
    73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
    75ff3a8a9168d ("Drivers: hv: vmbus: avoid wait_for_completion() on crash")
    76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
    8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
    a108393dbf764 ("drivers:hv: Export the API to invoke a hypercall on Hyper-V")
    d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")
Just from reading the subject lines it seems to me a lot of the possible
dependencies aren't really related to this patch functionally. It could
be that they are touching the same area of code which create some
contextual dependencies. Some of the listed dependencies should
definitively _not_ be backported.

Michael and Joseph, how far do you want this to be backported? It may be
easier for us to provide bespoke versions of this patch to the stable
trees we care about?

Wei.

NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?

-- 
Thanks
Sasha

Re: [PATCH][v2] Drivers: hv: Change flag to write log level in panic msg to false

From: Wei Liu <wei.liu@kernel.org>
Date: 2020-07-06 11:46:19 

Forgot to CC Michael.

On Mon, Jul 06, 2020 at 10:55:49AM +0000, Wei Liu wrote:
On Wed, Jul 01, 2020 at 07:33:25PM +0000, Sasha Levin wrote:
quoted
Hi

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all

The bot has tested the following trees: v5.7.6, v5.4.49, v4.19.130, v4.14.186, v4.9.228, v4.4.228.

v5.7.6: Build OK!
v5.4.49: Failed to apply! Possible dependencies:
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
Unrelated, shouldn't be backported.
quoted
v4.19.130: Failed to apply! Possible dependencies:
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
Unrelated, shouldn't be backported.
quoted
v4.14.186: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
    7ed4325a44ea5 ("Drivers: hv: vmbus: Make panic reporting to be more useful")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
    8afc06dd75c06 ("Drivers: hv: vmbus: Fix the issue with freeing up hv_ctl_table_hdr")
    ddcaf3ca4c3c8 ("Drivers: hv: vmus: Fix the check for return value from kmsg get dump buffer")

v4.9.228: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common code")
    73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
    76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
    8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
    d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")

v4.4.228: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    619848bd07434 ("drivers:hv: Export a function that maps Linux CPU num onto Hyper-V proc num")
    6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common code")
    73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
    75ff3a8a9168d ("Drivers: hv: vmbus: avoid wait_for_completion() on crash")
    76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
    8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
    a108393dbf764 ("drivers:hv: Export the API to invoke a hypercall on Hyper-V")
    d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")
Just from reading the subject lines it seems to me a lot of the possible
dependencies aren't really related to this patch functionally. It could
be that they are touching the same area of code which create some
contextual dependencies. Some of the listed dependencies should
definitively _not_ be backported.

Michael and Joseph, how far do you want this to be backported? It may be
easier for us to provide bespoke versions of this patch to the stable
trees we care about?

Wei.
quoted
NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?

-- 
Thanks
Sasha

RE: [PATCH][v2] Drivers: hv: Change flag to write log level in panic msg to false

From: Michael Kelley <hidden>
Date: 2020-07-06 13:28:15 

From: Wei Liu <wei.liu@kernel.org> Sent: Monday, July 6, 2020 3:56 AM
On Wed, Jul 01, 2020 at 07:33:25PM +0000, Sasha Levin wrote:
quoted
Hi

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: all

The bot has tested the following trees: v5.7.6, v5.4.49, v4.19.130, v4.14.186, v4.9.228,
v4.4.228.
quoted
v5.7.6: Build OK!
v5.4.49: Failed to apply! Possible dependencies:
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
Unrelated, shouldn't be backported.
quoted
v4.19.130: Failed to apply! Possible dependencies:
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
Unrelated, shouldn't be backported.
quoted
v4.14.186: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    53edce00ceb74 ("Drivers: hv: vmbus: Remove dependencies on guest page size")
    7ed4325a44ea5 ("Drivers: hv: vmbus: Make panic reporting to be more useful")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during
panic")
quoted
    8afc06dd75c06 ("Drivers: hv: vmbus: Fix the issue with freeing up hv_ctl_table_hdr")
    ddcaf3ca4c3c8 ("Drivers: hv: vmus: Fix the check for return value from kmsg get dump
buffer")
quoted
v4.9.228: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common
code")
quoted
    73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
    76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during
panic")
quoted
    8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
    d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")

v4.4.228: Failed to apply! Possible dependencies:
    4a5f3cde4d51c ("Drivers: hv: vmbus: Remove x86-isms from arch independent drivers")
    619848bd07434 ("drivers:hv: Export a function that maps Linux CPU num onto Hyper-V
proc num")
quoted
    6ab42a66d2cc1 ("Drivers: hv: vmbus: Move Hypercall invocation code out of common
code")
quoted
    73638cddaad86 ("Drivers: hv: vmbus: Move the check for hypercall page setup")
    75ff3a8a9168d ("Drivers: hv: vmbus: avoid wait_for_completion() on crash")
    76d36ab798204 ("hv: switch to cpuhp state machine for synic init/cleanup")
    81b18bce48af3 ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during
panic")
quoted
    8730046c1498e ("Drivers: hv vmbus: Move Hypercall page setup out of common code")
    a108393dbf764 ("drivers:hv: Export the API to invoke a hypercall on Hyper-V")
    d058fa7e98ff0 ("Drivers: hv: vmbus: Move the crash notification function")
Just from reading the subject lines it seems to me a lot of the possible
dependencies aren't really related to this patch functionally. It could
be that they are touching the same area of code which create some
contextual dependencies. Some of the listed dependencies should
definitively _not_ be backported.

Michael and Joseph, how far do you want this to be backported? It may be
easier for us to provide bespoke versions of this patch to the stable
trees we care about?
The code being changed was added in 4.19, so that's the earliest kernel version
to which it makes sense to backport.  53edce00ceb74 is an unrelated change
to the same line of code (changes PAGE_SIZE to HV_HYP_PAGE_SIZE), so a bespoke
version of this patch is needed for the stable trees.  All-in-all, this patch is a modest
optimization, so backporting is nice but not required.

Michael
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help