Re: [PATCH] Print utsname on Oops on all architectures

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 5 Jul 2007 18:52:27 -0700 (PDT) Joshua Wise <jwise@google.com> wrote:

> Background:
>  This patch is a follow-on to "Info dump on Oops or panic()" [1].
>  
>  On some architectures, the kernel printed some information on the running
>  kernel, but not on all architectures. The information printed was generally
>  the version and build number, but it was not located in a consistant place,
>  and some architectures did not print it at all.
> 
> Description:
>  This patch uses the already-existing die_chain to print utsname information
>  on Oops. This patch also removes the architecture-specific utsname
>  printers. To avoid crashing the system further (and hence not printing the
>  Oops) in the case where the system is so hopelessly smashed that utsname
>  might be destroyed, we vsprintf the utsname data into a static buffer
>  first, and then just print that on crash.
> 
> Testing:
>  I wrote a module that does a *(int*)0 = 0; and observed that I got my
>  utsname data printed.
> 
> Potential impact:
>  This adds another line to the Oops output, causing the first few lines to
>  potentially scroll off the screen. This also adds a few more pointer
>  dereferences in the Oops path, because it adds to the die_chain notifier
>  chain, reducing the likelihood that the Oops will be printed if there is
>  very bad memory corruption.

There are strange happenings due to this patch on i386:

Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
hdc: max request size: 128KiB
hdc: 156355584 sectors (80054 MB) w/1819KiB Cache, CHS=65535/16/63, UDMA(33)
hdc: cache flushes supported
 hdc:<0>Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
 hdc1 hdc2 hdc3 hdc4 <<0>Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
 hdc5<0>Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
 hdc6 >
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
initcall 0xc052a060: idedisk_init+0x0/0x10() returned 0.
initcall 0xc052a060 ran for 38 msecs: idedisk_init+0x0/0x10()
Calling initcall 0xc052a070: ide_cdrom_init+0x0/0x10()
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
initcall 0xc052a070: ide_cdrom_init+0x0/0x10() returned 0.
initcall 0xc052a070 ran for 3 msecs: ide_cdrom_init+0x0/0x10()
Calling initcall 0xc052a080: idetape_init+0x0/0x90()
initcall 0xc052a080: idetape_init+0x0/0x90() returned 0.
initcall 0xc052a080 ran for 0 msecs: idetape_init+0x0/0x90()
Calling initcall 0xc052a110: idefloppy_init+0x0/0x20()
ide-floppy driver 0.99.newide
initcall 0xc052a110: idefloppy_init+0x0/0x20() returned 0.
initcall 0xc052a110 ran for 0 msecs: idefloppy_init+0x0/0x20()
Calling initcall 0xc052a3e0: spi_transport_init+0x0/0x30()
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
Linux 2.6.23-rc1-mm1 #7 SMP Tue Jul 24 22:34:40 PDT 2007 i686
initcall 0xc052a3e0: spi_transport_init+0x0/0x30() returned 0.
initcall 0xc052a3e0 ran for 3 msecs: spi_transport_init+0x0/0x30()
Calling initcall 0xc052a410: fc_transport_init+0x0/0x50()
initcall 0xc052a410: fc_transport_init+0x0/0x50() returned 0.
initcall 0xc052a410 ran for 0 msecs: fc_transport_init+0x0/0x50()
Calling initcall 0xc052a460: init_sd+0x0/0x90()
initcall 0xc052a460: init_sd+0x0/0x90() returned 0.
initcall 0xc052a460 ran for 0 msecs: init_sd+0x0/0x90()

and it gets no further.

I'll drop it - let's start again?
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