Date:	Mon, 2 Nov 2015 06:47:29 +0000
From:	"Kweh, Hock Leong" <hock.leong.kweh@...el.com>
To:	'Borislav Petkov' <bp@...en8.de>
CC:	Matt Fleming <matt@...sole-pimps.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Ong, Boon Leong" <boon.leong.ong@...el.com>,
	LKML <linux-kernel@...r.kernel.org>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	Sam Protsenko <semen.protsenko@...aro.org>,
	Peter Jones <pjones@...hat.com>,
	Andy Lutomirski <luto@...capital.net>,
	"Roy Franz" <roy.franz@...aro.org>,
	James Bottomley <James.Bottomley@...senpartnership.com>,
	Linux FS Devel <linux-fsdevel@...r.kernel.org>,
	"Fleming, Matt" <matt.fleming@...el.com>,
	"Anvin, H Peter" <h.peter.anvin@...el.com>
Subject: RE: [PATCH v9 1/1] efi: a misc char interface for user to update
 efi firmware

> -----Original Message-----
> From: Borislav Petkov [mailto:bp@...en8.de]
> Sent: Sunday, November 01, 2015 6:30 PM
> >
> > Example method to load the capsule binary:
> > cat firmware.bin > /dev/efi_capsule_loader
> 
> $ cat "some_dumb_file" > /dev/efi_capsule_loader
> Killed
> 
> and in dmesg:
> 
> [   34.033982] efi_capsule_loader: efi_capsule_flush: capsule upload not
> complete

Hi Boris,

I have tested "cat /bin/ls > /dev/efi_capsule_loader" in my environment,
but I am not able to reproduce the issue. So, it is a bit hard for me to debug
the issue with my environment and may need your help on this.

By looking at your dmesg log, the above print out message seem that
someone has called the flush() after the write(2). In my environment, flush()
only being called in 2 places which are before write(2) and during close(2).
The dmesg log seems that your environment is running write(2) and flush() in
different threads and are parallel. Could you help me to double confirm this and it 
would be good if you could told me when the flush() is exactly being called in
your environment. The info really help me on debugging.

Thanks & Regards,
Wilson

> [   58.765683] ------------[ cut here ]------------
> [   58.769349] WARNING: CPU: 5 PID: 3904 at
> drivers/firmware/efi/capsule.c:83 efi_capsule_supported+0x103/0x150()
> [   58.775063] Modules linked in:
> [   58.776474] CPU: 5 PID: 3904 Comm: cat Not tainted 4.3.0-rc7+ #3
> [   58.779044] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> 1.7.5-20140531_083030-gandalf 04/01/2014
> [   58.783387]  ffffffff81957aa0 ffff880079793d78 ffffffff812cb2ea
> 0000000000000000
> [   58.786749]  ffff880079793db0 ffffffff81055981 00010102464c457f
> 0000000000000000
> [   58.790140]  0000000000401e3b 0000000000000001 ffff880078660704
> ffff880079793dc0
> [   58.793353] Call Trace:
> [   58.794343]  [<ffffffff812cb2ea>] dump_stack+0x4e/0x84
> [   58.796416]  [<ffffffff81055981>] warn_slowpath_common+0x91/0xd0
> [   58.798773]  [<ffffffff81055a7a>] warn_slowpath_null+0x1a/0x20
> [   58.800962]  [<ffffffff8157ae93>] efi_capsule_supported+0x103/0x150
> [   58.803292]  [<ffffffff8157d559>] efi_capsule_write+0x269/0x390
> [   58.805563]  [<ffffffff81183ef8>] __vfs_write+0x28/0xe0
> [   58.807591]  [<ffffffff81183e9a>] ? __vfs_read+0xaa/0xe0
> [   58.809612]  [<ffffffff811847d5>] vfs_write+0xb5/0x1a0
> [   58.811272]  [<ffffffff811a33be>] ? __fget_light+0x6e/0x90
> [   58.813073]  [<ffffffff81185412>] SyS_write+0x52/0xc0
> [   58.814720]  [<ffffffff816cff5b>] entry_SYSCALL_64_fastpath+0x16/0x73
> [   58.816665] ---[ end trace 94c0c141f9b0ec01 ]---
> [   58.818179] BUG: unable to handle kernel NULL pointer dereference at
> (null)
> [   58.820427] IP: [<          (null)>]           (null)
> [   58.820630] PGD 79af8067 PUD 79781067 PMD 0
> [   58.820630] Oops: 0010 [#1] PREEMPT SMP
> [   58.820630] Modules linked in:
> [   58.820630] CPU: 5 PID: 3904 Comm: cat Tainted: G        W       4.3.0-rc7+ #3
> [   58.820630] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> 1.7.5-20140531_083030-gandalf 04/01/2014
> [   58.820630] task: ffff8800771417c0 ti: ffff880079790000 task.ti:
> ffff880079790000
> [   58.820630] RIP: 0010:[<0000000000000000>]  [<          (null)>]           (null)
> [   58.820630] RSP: 0018:ffff880079793dc8  EFLAGS: 00010282
> [   58.820630] RAX: ffff88007a01b4e0 RBX: 00010102464c457f RCX:
> ffff880078660704
> [   58.820630] RDX: ffff880079793dd8 RSI: 0000000000000001 RDI:
> ffff880079793dd0
> [   58.820630] RBP: ffff880079793e08 R08: 0000000000000000 R09:
> 0000000000000000
> [   58.820630] R10: 0000000000000000 R11: 0000000000000001 R12:
> 0000000000000000
> [   58.820630] R13: 0000000000401e3b R14: 0000000000000001 R15:
> ffff880078660704
> [   58.820630] FS:  00007ffff7fe1700(0000) GS:ffff88007c000000(0000)
> knlGS:0000000000000000
> [   58.820630] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [   58.820630] CR2: 0000000000000000 CR3: 000000007ab90000 CR4:
> 00000000000406e0
> [   58.820630] Stack:
> [   58.820630]  ffffffff8157ae24 ffff88007a01b4e0 0000000000000002
> ffff880078660700
> [   58.820630]  ffff880077060000 0000000000001000 ffffea0001dc1800
> ffff880077060000
> [   58.820630]  ffff880079793e48 ffffffff8157d559 0000000000000402
> ffff8800799cbc00
> [   58.820630] Call Trace:
> [   58.820630]  [<ffffffff8157ae24>] ? efi_capsule_supported+0x94/0x150
> [   58.820630]  [<ffffffff8157d559>] efi_capsule_write+0x269/0x390
> [   58.820630]  [<ffffffff81183ef8>] __vfs_write+0x28/0xe0
> [   58.820630]  [<ffffffff81183e9a>] ? __vfs_read+0xaa/0xe0
> [   58.820630]  [<ffffffff811847d5>] vfs_write+0xb5/0x1a0
> [   58.820630]  [<ffffffff811a33be>] ? __fget_light+0x6e/0x90
> [   58.820630]  [<ffffffff81185412>] SyS_write+0x52/0xc0
> [   58.820630]  [<ffffffff816cff5b>] entry_SYSCALL_64_fastpath+0x16/0x73
> [   58.820630] Code:  Bad RIP value.
> [   58.820630] RIP  [<          (null)>]           (null)
> [   58.820630]  RSP <ffff880079793dc8>
> [   58.820630] CR2: 0000000000000000
> [   58.876221] ---[ end trace 94c0c141f9b0ec02 ]---
> 

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