linux-kernel - Re: [RFC] TIF_NOTIFY_RESUME, arch/*/*/*signal*.c and all such

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 1 May 2012 01:06:36 -0400
From:	Mike Frysinger <vapier@...too.org>
To:	Al Viro <viro@...iv.linux.org.uk>
Cc:	Chen Liqin <liqin.chen@...plusct.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
	Oleg Nesterov <oleg@...hat.com>
Subject: Re: [RFC] TIF_NOTIFY_RESUME, arch/*/*/*signal*.c and all such

On Tuesday 01 May 2012 00:31:29 Al Viro wrote:
> blackfin: no loop (== multiple signals handling is fucked); no check either
>         ret_from_fork doesn't handle signals, etc., userland or not.
>         kernel_execve doesn't handle signals, etc., success or no success
>         conclusion: check is probably not needed, multiple pending signals
> are screwed

to be honest, i haven't been following this thread as Blackfin wasn't mentioned 
in the initial summary.  now it seems we have ;).  i tried going back through 
this TIF_NOTIFY_RESUME thread but haven't quite got a bead on what needs to be 
done.

seems like you're only referring to ret_from_fork here and not the normal 
syscall return path ?  in the Blackfin case, we don't have a fork(), so we only 
have to handle the supervisor mode case (spawning kthreads), so i don't think 
we're quite as fucked as you might think :).

what is it you're suggesting we add ?  in the past, i found documentation on 
the arch TIF_*/notify requirements to be pretty much non-existent.  so some 
parts of the Blackfin paths are what i found from my eyes bleeding x86 asm 
paths, and from single testing some random tests (like strace or gdb).  things 
seem to run & be debugable, and no one has complained thus far, so we ship it!
-mike

Download attachment "signature.asc " of type "application/pgp-signature" (837 bytes)