ACK: [PATCH 0/2][SRC][BIONIC] fix zram kernel hard lockup (LP: #1799497)

[Sultan Alsawaf]

On Fri, Feb 07, 2020 at 04:27:52PM +0000, Colin King wrote:
> From: Colin Ian King <colin.king at canonical.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1799497
> 
> == SRU Justification [BIONIC ONLY] ==
> 
> When using zram (as installed and configured with the zram-config package)
> systems can lockup after about a week of use.  This occurs because of
> a hang in a lock in zram.
> 
> == Test Case ==
> 
> Run stress-ng --brk 0 --stack 0 in a Bionic amd64 server VM with 1GM of
> memory, 16 CPU threads and zram-config installed.  Without the fix the
> kernel will hang in a spinlock after 1-2 hours of run time. With the fix,
> the hang does not occur.  Testing shows that with the fix, 5 x 16 CPU hours
> of stress testing with stress-ng works fine without the lockup occurring.
> 
> == The fix ==
> 
> Upstream commit c4d6c4cc7bfd ("zram: correct flag name of ZRAM_ACCESS") as
> a prerequisite followed by a minor line wiggle backport of the fix with 
> commit 3c9959e02547 ("zram: fix lockdep warning of free block handling").
> 
> == Regression Potential ==
> 
> This touches the zram locking, so the core zram driver is affected. However
> the fixes are backports from 5.0, so the fixes have had a fair amount of
> testing in later kernels.
> 
> Minchan Kim (2):
>   zram: fix lockdep warning of free block handling
>   zram: correct flag name of ZRAM_ACCESS
> 
>  drivers/block/zram/zram_drv.c | 58 +++++++++++++++++++++++--------------------
>  drivers/block/zram/zram_drv.h |  8 +++---
>  2 files changed, 35 insertions(+), 31 deletions(-)
> 
> -- 
> 2.7.4
> 
> 
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Acked-by: Sultan Alsawaf <sultan.alsawaf at canonical.com>