Messages in this thread | | | Subject | Re: [PATCH v5 04/18] sparc32: mm: Reduce allocation size for PMD and PTE tables | From | Guenter Roeck <> | Date | Sun, 24 May 2020 07:01:35 -0700 |
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On 5/24/20 5:32 AM, Mike Rapoport wrote: > On Thu, May 21, 2020 at 04:02:11PM -0700, Guenter Roeck wrote: >> On 5/20/20 12:51 PM, Mike Rapoport wrote: >>> On Wed, May 20, 2020 at 12:03:31PM -0700, Guenter Roeck wrote: >>>> On 5/20/20 10:03 AM, Mike Rapoport wrote: >>>>> On Mon, May 18, 2020 at 09:37:15AM +0100, Will Deacon wrote: >>>>>> On Sat, May 16, 2020 at 05:07:50PM -0700, Guenter Roeck wrote: >>>>>>> On Sat, May 16, 2020 at 05:00:50PM -0700, Guenter Roeck wrote: >>>>>>>> On Mon, May 11, 2020 at 09:41:36PM +0100, Will Deacon wrote: >>>>>>>>> Now that the page table allocator can free page table allocations >>>>>>>>> smaller than PAGE_SIZE, reduce the size of the PMD and PTE allocations >>>>>>>>> to avoid needlessly wasting memory. >>>>>>>>> >>>>>>>>> Cc: "David S. Miller" <davem@davemloft.net> >>>>>>>>> Cc: Peter Zijlstra <peterz@infradead.org> >>>>>>>>> Signed-off-by: Will Deacon <will@kernel.org> >>>>>>>> >>>>>>>> Something in the sparc32 patches in linux-next causes all my sparc32 emulations >>>>>>>> to crash. bisect points to this patch, but reverting it doesn't help, and neither >>>>>>>> does reverting the rest of the series. >>>>>>>> >>>>>>> Actually, turns out I see the same pattern (lots of scheduling while atomic >>>>>>> followed by 'killing interrupt handler' in cryptomgr_test) with several >>>>>>> powerpc boot tests. I am currently bisecting those crashes. I'll report >>>>>>> the results here as well as soon as I have it. >>>>>> >>>>>> FWIW, I retested my sparc32 patches with PREEMPT=y and I don't see any >>>>>> issues. However, linux-next is a different story, where I don't get very far >>>>>> at all: >>>>>> >>>>>> BUG: Bad page state in process swapper pfn:005b4 >>>> >>>> With above patch applied on top of Ira's patch, I get: >>>> >>>> BUG: spinlock recursion on CPU#0, S01syslogd/139 >>>> lock: 0xf5448350, .magic: dead4ead, .owner: S01syslogd/139, .owner_cpu: 0 >>>> CPU: 0 PID: 139 Comm: S01syslogd Not tainted 5.7.0-rc6-next-20200518-00002-gb178d2d56f29-dirty #1 >>>> [f0067a64 : >>>> do_raw_spin_lock+0xa8/0xd8 ] >>>> [f00d5034 : >>>> copy_page_range+0x328/0x804 ] >>>> [f0025be4 : >>>> dup_mm+0x334/0x434 ] >>>> [f0027124 : >>>> copy_process+0x1224/0x12b0 ] >>>> [f0027344 : >>>> _do_fork+0x54/0x30c ] >>>> [f0027670 : >>>> do_fork+0x5c/0x6c ] >>>> [f000de44 : >>>> sparc_do_fork+0x18/0x38 ] >>>> [f000b7f4 : >>>> do_syscall+0x34/0x40 ] >>>> [5010cd4c : >>>> 0x5010cd4c ] >>>> >>>> Looks like yet another problem. >>> >>> I've checked the patch above on top of the mmots which already has Ira's >>> patches and it booted fine. I've used sparc32_defconfig to build the >>> kernel and qemu-system-sparc with default machine and CPU. >>> >> >> Try sparc32_defconfig+SMP. > > I see a differernt problem, but this could be related: > > INIT: version 2.86 booting > rcu: INFO: rcu_sched detected stalls on CPUs/tasks: > (detected by 0, t=5252 jiffies, g=-935, q=3) > rcu: All QSes seen, last rcu_sched kthread activity 5252 (-68674--73926), jiffies_till_next_fqs=1, root ->qsmask 0x0 > rcu: rcu_sched kthread starved for 5252 jiffies! g-935 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 > rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. > rcu: RCU grace-period kthread stack dump: > rcu_sched R running task 0 10 2 0x00000000 > > I'm running a bit old debian [1] with qemu-img-sparc. > > My bisect pointed at commit 8c8f3156dd40 ("sparc32: mm: Reduce > allocation size for PMD and PTE tables"). The commit ID is valid for > next-20200522. > Here is what I currently get:
next-20200522: All builds/tests crash next-20200522 plus upstream commit 0cfc8a8d70dc ("sparc32: fix page table traversal in srmmu_nocache_init()"): nosmp images (sparc32_defconfig) boot fine smp images (sparc32_defconfig+SMP) crash with "BUG: Bad page state" next-20200522 plus 0cfc8a8d70dc plus memblock_add() from below: smp images crash with spinlock recursion as above next-20200522 plus 0cfc8a8d70dc plus revert of 8c8f3156dd40: smp images crash with "BUG: Bad page state" next-20200522 plus 0cfc8a8d70dc plus revert of 8c8f3156dd40 plus memblock_add(): All builds/tests pass
This is with my root file system. I tried the debian image but I seem to be missing some command line option needed to make it work.
Guenter
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