Messages in this thread | | | Date | Fri, 29 Feb 2008 17:45:10 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86_64 ia32 syscall restart fix |
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* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> > > The code to restart syscalls after signals depends on checking for a > > > negative orig_ax, and for particular negative -ERESTART* values in ax. > > > These fields are 64 bits and for a 32-bit task they get zero-extended. > > > The syscall restart behavior is lost, a regression from a native > > > 32-bit kernel and from 64-bit tasks' behavior. This patch fixes the > > > problem by doing sign-extension where it matters. For orig_ax, the > > > only time the value should be -1 but winds up as 0x0ffffffff is via a > > > 32-bit ptrace call. So the patch changes ptrace to sign-extend the > > > 32-bit orig_eax value when it's stored; it doesn't change the checks > > > on orig_ax, though it uses the new current_syscall() inline to better > > > document the subtle importance of the used of signedness there. The > > > ax value is stored a lot of ways and it seems hard to get them all > > > sign-extended at their origins. So for that, we use the > > > current_syscall_ret() to sign-extend it only for 32-bit tasks at the > > > time of the -ERESTART* comparisons. > > > > thanks, applied. > > Btw, can we please try to keep commit log messages readable?
yeah - the minute i added the patch i pinged Roland about that offline.
> Yeah, maybe it's just me, but I like my whitespace. > Ihaveareallyhardtime > readingtextthatdoesn'thavethepropermarkersforwhereconceptsstartandbegin, > andthatreallydoesincludetheverticalwhitespacetoo.
heh :)
> Now, the only reason I mention this is that normally I would probably > just have fixed this up myself without even a comment (because it's > such a tiny detail that it's not not worth one), but when Ingo merges > it I'll now get it through git and it will be fixed.
currently the reality is that i have to fix over 90% of the commit messages that go towards you :-/
While i'd like that proportion to be a lot lower, it's really hard for people to write good commit messages for fixes: people tend to send their fixes the minute they find the problem (being happy about having found and fixed a problem!), so the commit message gets little attention.
another effect is that kernel generalist people like Roland have a very large list of todo items so when they write up the commit message they might be thinking about the next unsolved problem already - and the commit message becomes a quick, unstructured and semi-automatic brain-dump of all details in essence :-/
Also, who am i to complain about the commit message - i'm often the one who has put the bug in to begin with! [ So i'm perfectly happy with you volunteering to take over that role ;-) ]
But yes, it's easier for me too to sort and prioritize patches if their description has good structure, so i regularly try to remind high-volume patch submitters about that. ( With little success i have to say - commit messages seem to be suffering from the same curse of inattention as other types of documentation do :-/ )
Ingo
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