All of lore.kernel.org
 help / color / mirror / Atom feed
From: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Gavin Shan <gwshan-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	hramrach-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Subject: Re: [PATCH] drivers/of: Validate device node in __unflatten_device_tree()
Date: Tue, 9 Aug 2016 12:25:43 -0500	[thread overview]
Message-ID: <20160809172543.GA5041@rob-hp-laptop> (raw)
In-Reply-To: <1470035873-21072-1-git-send-email-gwshan-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>

On Mon, Aug 01, 2016 at 05:17:53PM +1000, Gavin Shan wrote:
> @mynodes is set to NULL when __unflatten_device_tree() is called
> to unflatten device sub-tree in PCI hot add scenario on PowerPC
> PowerNV platform. Marking @mynodes detached unconditionally causes
> kernel crash as below backtrace shows:
> 
> Unable to handle kernel paging request for data at address 0x00000000
> Faulting instruction address: 0xc000000000b26f64
> cpu 0x0: Vector: 300 (Data Access) at [c000003fcc7cf740]
>     pc: c000000000b26f64: __unflatten_device_tree+0xf4/0x190
>     lr: c000000000b26f40: __unflatten_device_tree+0xd0/0x190
>     sp: c000003fcc7cf9c0
>    msr: 900000000280b033
>    dar: 0
>  dsisr: 40000000
>   current = 0xc000003fcc281680
>   paca    = 0xc00000000ff00000	 softe: 0	 irq_happened: 0x01
>     pid   = 2724, comm = sh
> Linux version 4.7.0-gavin-07754-g92a6836 (gwshan@gwshan) (gcc version \
> 4.9.3 (Buildroot 2016.02-rc2-00093-g5ea3bce) ) #539 SMP Mon Aug 1 \
> 12:40:29 AEST 2016
> enter ? for help
> [c000003fcc7cfa50] c000000000b27060 of_fdt_unflatten_tree+0x60/0x90
> [c000003fcc7cfaa0] c0000000004c6288 pnv_php_set_slot_power_state+0x118/0x440
> [c000003fcc7cfb80] c0000000004c6a10 pnv_php_enable+0xc0/0x170
> [c000003fcc7cfbd0] c0000000004c4d80 power_write_file+0xa0/0x190
> [c000003fcc7cfc50] c0000000004be93c pci_slot_attr_store+0x3c/0x60
> [c000003fcc7cfc70] c0000000002d3fd4 sysfs_kf_write+0x94/0xc0
> [c000003fcc7cfcb0] c0000000002d2c30 kernfs_fop_write+0x180/0x260
> [c000003fcc7cfd00] c000000000230fe0 __vfs_write+0x40/0x190
> [c000003fcc7cfd90] c000000000232278 vfs_write+0xc8/0x240
> [c000003fcc7cfde0] c000000000233d90 SyS_write+0x60/0x110
> [c000003fcc7cfe30] c000000000009524 system_call+0x38/0x108
> 
> This avoids the kernel crash by marking @mynodes detached only when
> @mynodes is dereferencing valid device node in __unflatten_device_tree().
> 
> Fixes: 1d1bde550ea3 ("of: fdt: mark unflattened tree as detached")
> Reported-by: Meng Li <shlimeng-vtt25B2cwJLQT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Gavin Shan <gwshan-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> ---
>  drivers/of/fdt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks.

Rob
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

      parent reply	other threads:[~2016-08-09 17:25 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-01  7:17 [PATCH] drivers/of: Validate device node in __unflatten_device_tree() Gavin Shan
     [not found] ` <1470035873-21072-1-git-send-email-gwshan-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2016-08-09 17:25   ` Rob Herring [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160809172543.GA5041@rob-hp-laptop \
    --to=robh-dgejt+ai2ygdnm+yrofe0a@public.gmane.org \
    --cc=devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=gwshan-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org \
    --cc=hramrach-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
    --cc=robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.