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From: Ira Weiny <ira.weiny@intel.com>
To: Mike Rapoport <rppt@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
	Helge Deller <deller@gmx.de>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	"David S. Miller" <davem@davemloft.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Chris Zankel <chris@zankel.net>,
	Max Filippov <jcmvbkbc@gmail.com>,
	Dan Williams <dan.j.williams@intel.com>,
	linux-snps-arc@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org,
	linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org,
	linux-xtensa@linux-xtensa.org, dri-devel@lists.freedesktop.org,
	Christian Koenig <christian.koenig@amd.com>,
	Al Viro <viro@zeniv.linux.org.uk>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] arch/{mips,sparc,microblaze,powerpc}: Don't enable pagefault/preempt twice
Date: Thu, 4 Jun 2020 13:51:40 -0700
Message-ID: <20200604205140.GN1505637@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <20200604094133.GC202650@kernel.org>

On Thu, Jun 04, 2020 at 12:41:33PM +0300, Mike Rapoport wrote:
> On Wed, Jun 03, 2020 at 04:44:17PM -0700, Guenter Roeck wrote:
> > 
> > sparc32 smp images in next-20200603 still crash for me with a spinlock
> > recursion. s390 images hang early in boot. Several others (alpha, arm64,
> > various ppc) don't even compile. I can run some more bisects over time,
> > but this is becoming a full-time job :-(.
> 
> I've been able to bisect s390 hang to commit b614345f52bc ("x86/entry:
> Clarify irq_{enter,exit}_rcu()").
> 
> After this commit, lockdep_hardirq_exit() is called twice on s390 (and
> others) - one time in irq_exit_rcu() and another one in irq_exit():
> 
> /**
>  * irq_exit_rcu() - Exit an interrupt context without updating RCU
>  *
>  * Also processes softirqs if needed and possible.
>  */
> void irq_exit_rcu(void)
> {
> 	__irq_exit_rcu();
> 	 /* must be last! */
> 	lockdep_hardirq_exit();
> }
> 
> /**
>  * irq_exit - Exit an interrupt context, update RCU and lockdep
>  *
>  * Also processes softirqs if needed and possible.
>  */
> void irq_exit(void)
> {
> 	irq_exit_rcu();
> 	rcu_irq_exit();
> 	 /* must be last! */
> 	lockdep_hardirq_exit();
> }
> 
> Removing the call in irq_exit() make s390 boot again, and judgung by the
> x86 entry code, the comment /* must be last! */ is stale...

FWIW I got s390 to compile and this patch fixes s390 booting for me as well.

13:05:25 > /home/iweiny/dev/linux-build-test/rootfs/s390/run-qemu-s390.sh 
Build reference: next-20200603-4-g840714292d8c

Building s390:defconfig:initrd ... running ........... passed
Building s390:defconfig:virtio-blk-ccw:rootfs ... running ........... passed
Building s390:defconfig:scsi[virtio-ccw]:rootfs ... running ..............  passed
Building s390:defconfig:virtio-pci:rootfs ... running ........... passed
Building s390:defconfig:scsi[virtio-pci]:rootfs ... running ........... passed

Ira

> 
> @Peter, @Thomas, can you comment please?
> 
> From e51d50ee6f4d1f446decf91c2c67230da14ff82c Mon Sep 17 00:00:00 2001
> From: Mike Rapoport <rppt@linux.ibm.com>
> Date: Thu, 4 Jun 2020 12:37:03 +0300
> Subject: [PATCH] softirq: don't call lockdep_hardirq_exit() twice
> 
> After commit b614345f52bc ("x86/entry: Clarify irq_{enter,exit}_rcu()")
> lockdep_hardirq_exit() is called twice on every architecture that uses
> irq_exit(): one time in irq_exit_rcu() and another one in irq_exit().
> 
> Remove the extra call in irq_exit().
> 
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
>  kernel/softirq.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/kernel/softirq.c b/kernel/softirq.c
> index a3eb6eba8c41..7523f4ce4c1d 100644
> --- a/kernel/softirq.c
> +++ b/kernel/softirq.c
> @@ -427,7 +427,6 @@ static inline void __irq_exit_rcu(void)
>  void irq_exit_rcu(void)
>  {
>  	__irq_exit_rcu();
> -	 /* must be last! */
>  	lockdep_hardirq_exit();
>  }
>  
> @@ -440,8 +439,6 @@ void irq_exit(void)
>  {
>  	irq_exit_rcu();
>  	rcu_irq_exit();
> -	 /* must be last! */
> -	lockdep_hardirq_exit();
>  }
>  
>  /*
> -- 
> 2.26.2
> 
> 
> 
> > Guenter
> 
> -- 
> Sincerely yours,
> Mike.

  reply index

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-07 14:59 [PATCH V3 00/15] Remove duplicated kmap code ira.weiny
2020-05-07 14:59 ` [PATCH V3 01/15] arch/kmap: Remove BUG_ON() ira.weiny
2020-05-07 14:59 ` [PATCH V3 02/15] arch/xtensa: Move kmap build bug out of the way ira.weiny
2020-05-07 14:59 ` [PATCH V3 03/15] arch/kmap: Remove redundant arch specific kmaps ira.weiny
2020-05-07 14:59 ` [PATCH V3 04/15] arch/kunmap: Remove duplicate kunmap implementations ira.weiny
2020-05-07 14:59 ` [PATCH V3 05/15] {x86,powerpc,microblaze}/kmap: Move preempt disable ira.weiny
2020-05-07 14:59 ` [PATCH V3 06/15] arch/kmap_atomic: Consolidate duplicate code ira.weiny
2020-05-07 14:59 ` [PATCH V3 07/15] arch/kunmap_atomic: " ira.weiny
2020-05-16 22:33   ` Guenter Roeck
2020-05-18  3:49     ` Ira Weiny
2020-05-18  4:29       ` Guenter Roeck
2020-05-18 18:11         ` Ira Weiny
2020-05-19  0:03         ` Ira Weiny
2020-05-19  2:50           ` Guenter Roeck
2020-05-19 16:29             ` Ira Weiny
2020-05-18 16:11       ` Guenter Roeck
2020-05-18 18:48   ` [PATCH] arch/{mips,sparc,microblaze,powerpc}: Don't enable pagefault/preempt twice ira.weiny
2020-05-19 16:54     ` Guenter Roeck
2020-05-19 18:40       ` Ira Weiny
2020-05-19 19:42         ` Guenter Roeck
2020-05-20  5:02           ` Ira Weiny
2020-05-20  5:13           ` Ira Weiny
2020-05-21 16:05             ` Guenter Roeck
2020-05-21 17:42               ` Ira Weiny
2020-05-21 22:27                 ` Guenter Roeck
2020-05-21 22:36                   ` Weiny, Ira
2020-06-03 20:57                 ` Andrew Morton
2020-06-03 21:14                   ` Ira Weiny
2020-06-03 23:44                     ` Guenter Roeck
2020-06-04  6:18                       ` Mike Rapoport
2020-06-04  6:43                         ` Ira Weiny
2020-06-04  6:22                       ` Ira Weiny
2020-06-04  6:37                         ` Mike Rapoport
2020-06-04  6:44                           ` Ira Weiny
2020-06-04  9:38                         ` Guenter Roeck
2020-06-04  9:41                       ` Mike Rapoport
2020-06-04 20:51                         ` Ira Weiny [this message]
2020-05-21 15:14           ` Ira Weiny
2020-05-21 17:27       ` Al Viro
2020-05-21 22:20         ` Guenter Roeck
2020-05-21 22:46           ` Al Viro
2020-05-22  0:46             ` Al Viro
2020-05-22  1:11               ` Guenter Roeck
2020-05-22  1:29                 ` Al Viro
2020-05-22  1:35                   ` Al Viro
2020-05-22  2:28                     ` Guenter Roeck
2020-05-07 14:59 ` [PATCH V3 08/15] arch/kmap: Ensure kmap_prot visibility ira.weiny
2020-05-07 14:59 ` [PATCH V3 09/15] arch/kmap: Don't hard code kmap_prot values ira.weiny
2020-05-07 14:59 ` [PATCH V3 10/15] arch/kmap: Define kmap_atomic_prot() for all arch's ira.weiny
2020-05-17 17:37   ` Guenter Roeck
2020-05-18 18:17     ` Ira Weiny
2020-05-07 14:59 ` [PATCH V3 11/15] drm: Remove drm specific kmap_atomic code ira.weiny
2020-05-07 15:00 ` [PATCH V3 12/15] kmap: Remove kmap_atomic_to_page() ira.weiny
2020-05-07 15:00 ` [PATCH V3 13/15] parisc/kmap: Remove duplicate kmap code ira.weiny
2020-05-07 20:52   ` Andrew Morton
2020-05-07 22:50     ` Ira Weiny
2020-05-07 15:00 ` [PATCH V3 14/15] sparc: Remove unnecessary includes ira.weiny
2020-05-07 15:00 ` [PATCH V3 15/15] kmap: Consolidate kmap_prot definitions ira.weiny
2020-05-07 20:53   ` Andrew Morton
2020-05-07 22:51     ` Ira Weiny
2020-05-07 22:52   ` [PATCH V3.1] " ira.weiny

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