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 joseph.salisbury@microsoft.com --- 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);
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 joseph.salisbury@microsoft.com
Applied to hyperv-fixes with Michael's review from v1. Thanks.
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
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?
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
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:
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
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:
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 dumpbuffer")
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 duringpanic")
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 commoncode")
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 duringpanic")
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
linux-stable-mirror@lists.linaro.org
-
Joseph Salisbury -
Michael Kelley -
Sasha Levin -
Wei Liu