Re: [PATCH 4/4] mm/vmalloc: Hugepage vmalloc mappings

From: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 4/4] mm/vmalloc: Hugepage vmalloc mappings
Date: Mon, 10 Jun 2019 13:38:25 +0530	[thread overview]
Message-ID: <20190610080825.GA11397@sathnaga86> (raw)
In-Reply-To: <1560145722.obq2bpepl8.astroid@bobo.none>

On Mon, Jun 10, 2019 at 03:49:48PM +1000, Nicholas Piggin wrote:
> Nicholas Piggin's on June 10, 2019 2:38 pm:
> > +static int vmap_hpages_range(unsigned long start, unsigned long end,
> > +			   pgprot_t prot, struct page **pages,
> > +			   unsigned int page_shift)
> > +{
> > +	BUG_ON(page_shift != PAGE_SIZE);
> > +	return vmap_pages_range(start, end, prot, pages);
> > +}
> 
> That's a false positive BUG_ON for !HUGE_VMAP configs. I'll fix that
> and repost after a round of feedback.

Sure, Crash log for that false positive BUG_ON on Power8 Host.

[    0.001718] pid_max: default: 163840 minimum: 1280
[    0.010437] ------------[ cut here ]------------
[    0.010461] kernel BUG at mm/vmalloc.c:473!
[    0.010471] Oops: Exception in kernel mode, sig: 5 [#1]
[    0.010481] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV
[    0.010491] Modules linked in:
[    0.010503] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.2.0-rc3-ga7ee9421d #1
[    0.010515] NIP:  c00000000034dbd8 LR: c00000000034dc80 CTR: 0000000000000000
[    0.010527] REGS: c0000000015bf9a0 TRAP: 0700   Not tainted  (5.2.0-rc3-ga7ee9421d)
[    0.010537] MSR:  9000000002029033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE>  CR: 22022422  XER: 20000000
[    0.010559] CFAR: c00000000034dc88 IRQMASK: 0
[    0.010559] GPR00: c00000000034dc80 c0000000015bfc30 c0000000015c2f00 c00c000001fd0e00
[    0.010559] GPR04: 0000000000000000 0000000000002322 0000000000000000 0000000000000040
[    0.010559] GPR08: c000000ff9080000 0000000000000400 0000000000000400 0000000000000100
[    0.010559] GPR12: 0000000042022422 c0000000017a0000 00000001035ae7d8 0000000000000400
[    0.010559] GPR16: 0000000004000000 800000000000018e c000000000ee08c8 0000000000000000
[    0.010559] GPR20: 0000000000010000 0000000000002b22 0000000000000b20 0000000000000022
[    0.010559] GPR24: c0000007f92c7880 0000000000000b22 0000000000010000 c00a000000000000
[    0.010559] GPR28: c008000000000000 0000000004000000 ffffffffffffffff 0000000000000b20
[    0.010664] NIP [c00000000034dbd8] __vmalloc_node_range+0x1f8/0x410
[    0.010677] LR [c00000000034dc80] __vmalloc_node_range+0x2a0/0x410
[    0.010686] Call Trace:
[    0.010695] [c0000000015bfc30] [c00000000034dc80] __vmalloc_node_range+0x2a0/0x410 (unreliable)
[    0.010711] [c0000000015bfd30] [c00000000034de40] __vmalloc+0x50/0x60
[    0.010724] [c0000000015bfda0] [c00000000101e54c] alloc_large_system_hash+0x200/0x304
[    0.010738] [c0000000015bfe60] [c0000000010235bc] vfs_caches_init+0xd8/0x138
[    0.010752] [c0000000015bfee0] [c000000000fe428c] start_kernel+0x5c4/0x668
[    0.010767] [c0000000015bff90] [c00000000000b774] start_here_common+0x1c/0x528
[    0.010777] Instruction dump:
[    0.010785] 60000000 7c691b79 418200dc e9180020 79ea1f24 7d28512a 40920170 8138002c
[    0.010803] 394f0001 794f0020 7c095040 4181ffbc <0fe00000> 60000000 3f400001 4bfffedc
[    0.010826] ---[ end trace dd0217488686d653 ]---
[    0.010834]
[    1.010946] Kernel panic - not syncing: Attempted to kill the idle task!
[    1.011061] Rebooting in 10 seconds..

Regards,
-Satheesh.
> 
> Thanks,
> Nick
> 
> 