[lkml]   [2018]   [Nov]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v3 1/7] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()"
On Fri, 2 Nov 2018, Nadav Amit wrote:

> text_mutex is expected to be held before text_poke() is called, but we
> cannot add a lockdep assertion since kgdb does not take it, and instead
> *supposedly* ensures the lock is not taken and will not be acquired by
> any other core while text_poke() is running.
> The reason for the "supposedly" comment is that it is not entirely clear
> that this would be the case if gdb_do_roundup is zero.
> Add a comment to clarify this behavior, and restore the assertions as
> they were before the recent commit.

It restores nothing. It just removes the assertion.

> This partially reverts commit 9222f606506c ("x86/alternatives:
> Lockdep-enforce text_mutex in text_poke*()")

That opens up the same can of worms again, which took us a while to close.

Can we please instead split out the text_poke() code into a helper function
and have two callers:

text_poke() which contains the assert

text_poke_kgdb() which does not



 \ /
  Last update: 2018-11-04 21:58    [W:0.218 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site