Re: patch to fix memory leak (when ex file completion results in no match)
- Dominique Pelle wrote:
> I can reproduce a memory leak 100% of the time in vim-7.1.123:I don't think this helps, because I can't find a combination of
> Start vim with:
> vim -u NONE -U NONE
> Then set the following options:
> :set nocompatible
> :set wildmode=longest,list
> :set wildmenu
> vim will then leak memory whenever file completion on Ex command
> results in no match:
> :e /<TAB> # OK no leak (file completion lists some files
> # /usr, /tmp, /dev, etc)
> :e /fff<TAB> # leaks 1 block of memory! (assuming no filename start
> # with /fff)
> Here is stack of the leak reported by valgrind (when exiting vim):
> ==12117== 21 bytes in 4 blocks are definitely lost in loss record 2 of 15
> ==12117== at 0x4021620: malloc (vg_replace_malloc.c:149)
> ==12117== by 0x8102F1C: lalloc (misc2.c:857)
> ==12117== by 0x8102E3E: alloc (misc2.c:756)
> ==12117== by 0x81032C9: vim_strnsave (misc2.c:1155)
> ==12117== by 0x80B00F9: nextwild (ex_getln.c:3254)
> ==12117== by 0x80AC44B: getcmdline (ex_getln.c:793)
> ==12117== by 0x80AE69B: getexline (ex_getln.c:2078)
> ==12117== by 0x8098E80: do_cmdline (ex_docmd.c:995)
> ==12117== by 0x8116F0F: nv_colon (normal.c:5168)
> ==12117== by 0x8111043: normal_cmd (normal.c:1141)
> ==12117== by 0x80D7D22: main_loop (main.c:1181)
> ==12117== by 0x80D7936: main (main.c:940)
> Here is the relevant code where memory is allocated:
> 3254 p2 = ExpandOne(xp, p1, vim_strnsave(&ccline.cmdbuff[i], oldlen),
> 3255 WILD_HOME_REPLACE|WILD_ADD_SLASH|WILD_SILENT|WILD_ESCAPE
> 3256 |options, type);
> Function vim_strnsave() allocates a block of memory and passes
> it to function ExpanOne (3rd argument).
> Adding some printf(), I can see that function ExpandOne()
> returns without freeing its 3rd argument at line 3414:
> 3413 if (mode == WILD_FREE) /* only release file name */
> 3414 return NULL;
> I think function ExpandOne() should free its 3rd argument
> before returning at line 3414.
WILD_FREE being used with the third argument not being NULL.
> There are also 3 other lines in ExpandOne() where it can potentiallyI don't think this helps. The normal return at the end of the function
> return without freeing its 3rd argument at lines 3396, 3397 and 3400
> (though I am not sure whether they can happen in practice). I did
> not fix them but they could possibly be other leaks.
> I attach a patch which fixes the leak at line 3414 which I can
> reproduce as explained above.
may leak memory when "orig" was not saved in "orig_save". This patch
should fix the leak:
*** ../../vim-7.1.126/src/ex_getln.c Sat Sep 29 14:15:00 2007
--- ex_getln.c Sun Sep 30 17:55:47 2007
*** 3540,3545 ****
--- 3544,3553 ----
if (mode == WILD_EXPAND_FREE || mode == WILD_ALL)
+ /* Free "orig" if it wasn't stored in "orig_save". */
+ if (orig != orig_save)
Please verify this fixes the leak, also without your suggested patch.
I tried your example and it appears to fix it. But I have not tried
every possible completion.
> Note that it's OK to have one block reported as leak (which isI thought that valgrind does check static variables and doesn't report a
> actually not a leak because there is a static var orig_save
> to cache I think) but it's not OK to leak more than one block.
leak when there is a pointer that uses the allocated memory.
> I'm using vim-7.1 (patches 1-123), on Linux, built withI don't check building with EXITFREE and various features. I think the
> 'configure --with-features=huge'
> I built vim by uncommenting out "PROFILE_CFLAGS = -DEXITFREE"
> in vim7/src/Makefile to help find leaks. After uncommenting that line,
> I had a compilation error (clip_exclude_prog() not declared):
> gcc -c -I. -Iproto -DHAVE_CONFIG_H -g -O0 -Wall
> -Wmissing-prototypes -DEXITFREE -o objects/misc2.o misc2.c
> misc2.c: In function 'free_all_mem':
> misc2.c:1040: error: 'clip_exclude_prog' undeclared (first use in this function)
> misc2.c:1040: error: (Each undeclared identifier is reported only once
> misc2.c:1040: error: for each function it appears in.)
> I worked around that error by moving clip_exclude_prog() declaration out
> of #ifdef FEAT_CLIPBOARD ... #endif. Should that be fixed too or is
> there a better way to define EXITFREE in the build?
right fix is to put that line in free_all_mem() inside #ifdef
*** /home/mool/vim/vim-7.1.126/src/misc2.c Sat Sep 29 14:15:00 2007
--- misc2.c Sun Sep 30 18:00:09 2007
*** 1037,1043 ****
--- 1038,1046 ----
/* Free some global vars. */
+ # ifdef FEAT_CLIPBOARD
+ # endif
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