Re: toolchain/54090 (gcc -fsanitize=address creates an unusable binary on amd64)

[Alexander Nasonov <alnsn%yandex.ru@localhost>]

The following reply was made to PR toolchain/54090; it has been noted by GNATS.

From: Alexander Nasonov <alnsn%yandex.ru@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: toolchain-manager%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost,
	gnats-admin%netbsd.org@localhost, maya%NetBSD.org@localhost, alnsn%netbsd.org@localhost
Subject: Re: toolchain/54090 (gcc -fsanitize=address creates an unusable
 binary on amd64)
Date: Wed, 29 May 2019 18:26:23 +0100

 maya%NetBSD.org@localhost wrote:
 > Synopsis: gcc -fsanitize=address creates an unusable binary on amd64
 > 
 > State-Changed-From-To: open->feedback
 > State-Changed-By: maya%NetBSD.org@localhost
 > State-Changed-When: Tue, 28 May 2019 07:16:14 +0000
 > State-Changed-Why:
 > I believe christos has fixed this. Is it working for you?
 
 It works when /proc is mounted with the "linux" flag and complains
 about missing /proc/<<pid>>/task otherwise.
 
 So, anyone who can recognise a linuxism here should be able to
 figure out that /proc needs to be remounted with the "linux" flag.
 
 It's not ideal but it's fine by me.
 
 --
 Alex
 
 #include <stdlib.h>
 int main() { malloc(4); return 0; }
 
 # umount /proc
 # mount_procfs -o linux none /proc
 
 $ ./a.out
 
 =================================================================
 ==14901==ERROR: LeakSanitizer: detected memory leaks
 
 Direct leak of 4 byte(s) in 1 object(s) allocated from:
     #0 0x740abda260f8 in __interceptor_malloc /home/alnsn/netbsd-current/sljit/src/external/gpl3/gcc/dist/libsanitizer/asan/asan_malloc_linux.cc:67
     #1 0x400a47 in main (/private/tmp/1000/./a.out+0x400a47)
     #2 0x40096c in ___start (/private/tmp/1000/./a.out+0x40096c)
 
 SUMMARY: AddressSanitizer: 4 byte(s) leaked in 1 allocation(s).
 HUP
 
 # umount /proc
 # mount_procfs -o nolinux none /proc
 
 $ ./a.out
 ==15703==Can't open /proc/13091/task for reading.
 ==13091==LeakSanitizer has encountered a fatal error.
 ==13091==HINT: For debugging, try setting environment variable LSAN_OPTIONS=verbosity=1:log_threads=1
 ==13091==HINT: LeakSanitizer does not work under ptrace (strace, gdb, etc)