[PATCH] kdump: Fix crash_kexec - smp_send_stop race in panic
James.Bottomley at HansenPartnership.com
Fri Nov 11 07:30:08 EST 2011
On Fri, 2011-11-11 at 13:28 +0100, Michael Holzheu wrote:
> Hello Chris,
> On Thu, 2011-11-10 at 10:11 -0500, Chris Metcalf wrote:
> > On 11/10/2011 9:22 AM, Michael Holzheu wrote:
> > If a cleaner API seems useful (either for power reasons or restartability
> > or whatever), I suppose a standard global function name could be specified
> > that's the thing you execute when you get an smp_send_stop IPI (in tile's
> > case it's "smp_stop_cpu_interrupt()") and the panic() code could instead
> > just do an atomic_inc_return() of a global panic counter, and if it wasn't
> > the first panicking cpu, call directly into the smp_stop handler routine to
> > quiesce itself. Then the panicking cpu could finish whatever it needs to
> > do and then halt, reboot, etc., all the cpus.
> Thanks for the info. So introducing a "weak" function that can stop the
> CPU it is running on could solve the problem. Every architecture can
> override the function with something appropriate. E.g. "tile" can use
> the lower-power "nap" instruction there.
> What about the following patch.
Since we're discussing architecture stuff, could we move back to the
architecture list? This thread keeps moving off it and it's not
More information about the kexec