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* btrfs-progs v3.14 mkfs.btrfs bug: --features long-option segfaults, -O short-option OK
@ 2014-04-16  6:41 Duncan
  2014-04-16  7:48 ` Holger Hoffstätte
  0 siblings, 1 reply; 3+ messages in thread
From: Duncan @ 2014-04-16  6:41 UTC (permalink / raw)
  To: linux-btrfs

Using btrfs-progs v3.14:

mkfs.btrfs ... --features ...

segfaults.

mkfs.btrfs ... -O ...

works fine.

* I used other long options, so it's not simply a problem parsing long 
options.

* I tried the long option with various features; none worked, including 
--features list-all with no other options.  That too segfaulted, tho -O 
list-all worked.

Segfault line as logged:

mkfs.btrfs[5231]: segfault at 0 ip 00007fb531c7ab1a sp 00007fffaf1a7a78 
error 4 in libc-2.19.so[7fb531bf8000+19a000]

btrfs-progs v3.14 from git on kernel v3.14 from git, gentoo/~amd64, built 
with gcc-4.8.2, using glibc-2.19.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: btrfs-progs v3.14 mkfs.btrfs bug: --features long-option segfaults, -O short-option OK
  2014-04-16  6:41 btrfs-progs v3.14 mkfs.btrfs bug: --features long-option segfaults, -O short-option OK Duncan
@ 2014-04-16  7:48 ` Holger Hoffstätte
  2014-04-16  7:55   ` Holger Hoffstätte
  0 siblings, 1 reply; 3+ messages in thread
From: Holger Hoffstätte @ 2014-04-16  7:48 UTC (permalink / raw)
  To: linux-btrfs

On Wed, 16 Apr 2014 06:41:44 +0000, Duncan wrote:

> Using btrfs-progs v3.14:
> 
> mkfs.btrfs ... --features ...
> 
> segfaults.

Can reproduce (also with glibc 2.19 on Gentoo ;-) and building with debug
found:

(gdb) bt
#0  0x00007ffff6f3aaea in strlen () from /lib64/libc.so.6
#1  0x00007ffff6f3a82e in strdup () from /lib64/libc.so.6
#2  0x00000000004213e8 in main (ac=2, av=0x7fffffffe308) at mkfs.c:1312

Sure enough that line is handling 'O', where '--features' is supposed to
be handled. No idea why -O works, but debugging shows that optarg is null
at that point, so strdup goes poof.

-h


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: btrfs-progs v3.14 mkfs.btrfs bug: --features long-option segfaults, -O short-option OK
  2014-04-16  7:48 ` Holger Hoffstätte
@ 2014-04-16  7:55   ` Holger Hoffstätte
  0 siblings, 0 replies; 3+ messages in thread
From: Holger Hoffstätte @ 2014-04-16  7:55 UTC (permalink / raw)
  To: linux-btrfs

On Wed, 16 Apr 2014 07:48:53 +0000, Holger Hoffstätte wrote:

> On Wed, 16 Apr 2014 06:41:44 +0000, Duncan wrote:
> 
>> Using btrfs-progs v3.14:
>> 
>> mkfs.btrfs ... --features ...
>> 
>> segfaults.
> 
> Can reproduce (also with glibc 2.19 on Gentoo ;-) and building with debug
> found:
> 
> (gdb) bt
> #0  0x00007ffff6f3aaea in strlen () from /lib64/libc.so.6
> #1  0x00007ffff6f3a82e in strdup () from /lib64/libc.so.6
> #2  0x00000000004213e8 in main (ac=2, av=0x7fffffffe308) at mkfs.c:1312
> 
> Sure enough that line is handling 'O', where '--features' is supposed to
> be handled. No idea why -O works, but debugging shows that optarg is null
> at that point, so strdup goes poof.

Well, duh! The long_options array does not declare that --features wants
an argument, so getopt does not create one.

holger>diff -u mkfs.c\~ mkfs.c
--- mkfs.c~	2014-04-16 09:41:42.000000000 +0200
+++ mkfs.c	2014-04-16 09:51:45.408854096 +0200
@@ -350,7 +350,7 @@
 	{ "version", 0, NULL, 'V' },
 	{ "rootdir", 1, NULL, 'r' },
 	{ "nodiscard", 0, NULL, 'K' },
-	{ "features", 0, NULL, 'O' },
+	{ "features", 1, NULL, 'O' },
 	{ NULL, 0, NULL, 0}
 };

This fixes it.

-h


^ permalink raw reply	[flat|nested] 3+ messages in thread

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2014-04-16  6:41 btrfs-progs v3.14 mkfs.btrfs bug: --features long-option segfaults, -O short-option OK Duncan
2014-04-16  7:48 ` Holger Hoffstätte
2014-04-16  7:55   ` Holger Hoffstätte

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