Package: libc6-dev
Version: 2.13-16
Severity: important
----- Forwarded message from David Miller <da...@davemloft.net> -----
Date: Sun, 14 Aug 2011 00:29:18 -0700 (PDT)
From: David Miller <da...@davemloft.net>
To: ju...@wooyd.org
CC: debian-sp...@lists.debian.org
Subject: [PATCH] Serious glibc sparc rlimits bug
X-Mailer: Mew version 6.3 on Emacs 23.2 / Mule 6.0 (HANACHIRUSATO)
Unfortunately, the sparc32 definition of the 64-bit RLIM_INFINITY
value is wrong, and it's been wrong for a while.
This causes serious problems, the worst of which is that no 64-bit
pthread program executing as a child of 'make' can succeed.
GLIBC's pthread_create() uses the current RLIMIT_STACK value as a hint
for sizing thread stacks. It handles RLIM_INFINITY specially instead
of trying to allocate an enormous stack.
But if RLIM_INFINITY is wrong... right, nothing works.
How this happens is that libpam corrupts the kernel default rlimits
when it creates a login session, because even if you have no explicit
settings in /etc/security/limits.conf it still reads every rlimit
then sets it right back to the same value. It even has some pre-cooked
defaults, and the default for RLIMIT_STACK is cur=8MB max=RLIM_INFINITY
So if RLIM_INFINITY is wrong (for 32-bit binaries it's too small), the
values will all get truncated down to this incorrect RLIM_INFINITY
value.
Next, make sets the current RLIMIT_STACK 'cur' value to the maximum,
so now the current RLIMIT_STACK has this wrong RLIM_INFINITY value
too.
Then 64-bit glibc doesn't recognize this value as RLIM_INFINITY during
pthread_create() and it tries to allocate a thread stack of size
0x8000000000000000 bytes. This, of course, fails.
A bunch of binaries are going to need to be rebuilt because of this issue
once the glibc build goes through, I would prioritize libpam0g, make,
and emacs23.
I'll be committing this soon to glibc GIT. I tested this by doing a
glibc deb rebuild with this patch applied, installing, then rebuilding
libpam0g and make.
2011-08-14 David S. Miller <da...@davemloft.net>
* sysdeps/unix/sysv/linux/sparc/bits/resource.h (RLIM_INFINITY,
RLIM64_INFINITY): Fix 64-bit values for 32-bit sparc.
diff --git a/sysdeps/unix/sysv/linux/sparc/bits/resource.h
b/sysdeps/unix/sysv/linux/sparc/bits/resource.h
index 04d33e4..5c00b8f 100644
--- a/sysdeps/unix/sysv/linux/sparc/bits/resource.h
+++ b/sysdeps/unix/sysv/linux/sparc/bits/resource.h
@@ -130,11 +130,11 @@ enum __rlimit_resource
#ifndef __USE_FILE_OFFSET64
# define RLIM_INFINITY ((long int)(~0UL >> 1))
#else
-# define RLIM_INFINITY 0x7fffffffffffffffLL
+# define RLIM_INFINITY 0xffffffffffffffffLL
#endif
#ifdef __USE_LARGEFILE64
-# define RLIM64_INFINITY 0x7fffffffffffffffLL
+# define RLIM64_INFINITY 0xffffffffffffffffLL
#endif
#endif
----- End forwarded message -----
--
Jurij Smakov ju...@wooyd.org
Key: http://www.wooyd.org/pgpkey/ KeyID: C99E03CC
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