Re: [PATCH 2/3] dfa: new option DFA_STRAY_BACKSLASH_WARN

[Jim Meyering]

On Mon, Jun 6, 2022 at 3:06 PM Paul Eggert <eggert@cs.ucla.edu> wrote:
> On 6/6/22 12:37, Jim Meyering wrote:
> > Once you push that (and assuming you have nothing else pending), I'll
> > prepare another pre-release snapshot.
>
> Thanks, I pushed it into grep master, after fixing the commentary issue
> Bruno noted.

I was going to make a snapshot, but figured I should first run the
usual *SAN check:
i.e., configure && make as usual, but then "make clean" followed by
this on a linux system:

san='-fsanitize-address-use-after-scope -fsanitize=address
-static-libasan';
ASAN_OPTIONS=detect_leaks=1,allocator_may_return_null=1 make
CFLAGS='-O0 -ggdb3' AM_CFLAGS="$san" AM_LDFLAGS="$san" check

and it failed nearly every test, all due to leaks.

You can see a few leaks with an even simpler test using valgrind and a
no-ASAN binary:
(this was with the patch attached below, which fixed the first one I found)

$ valgrind --leak-check=full src/grep a /dev/null
==233608== Memcheck, a memory error detector
==233608== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
==233608== Using Valgrind-3.19.0 and LibVEX; rerun with -h for copyright info
==233608== Command: src/grep a /dev/null
==233608==
==233608==
==233608== HEAP SUMMARY:
==233608==     in use at exit: 112,578 bytes in 27 blocks
==233608==   total heap usage: 162 allocs, 135 frees, 140,110 bytes allocated
==233608==
==233608== 16 bytes in 1 blocks are definitely lost in loss record 7 of 25
==233608==    at 0x484486F: malloc (vg_replace_malloc.c:381)
==233608==    by 0x4275DE: analyze (regcomp.c:1131)
==233608==    by 0x4275DE: re_compile_internal (regcomp.c:769)
==233608==    by 0x428327: rpl_re_compile_pattern (regcomp.c:217)
==233608==    by 0x405084: regex_compile (dfasearch.c:164)
==233608==    by 0x4053CA: Gearch.c:265)
==233608==    by 0x404427: main (grep.c:2975)
==233608==
==233608== 32 bytes in 1 blocks are definitely lost in loss record 10 of 25
==233608==    at 0x484486F: malloc (vg_replace_malloc.c:381)
==233608==    by 0x427156: init_dfa (regcomp.c:827)
==233608==    by 0x427156: re_compile_internal (regcomp.c:732)
==233608==    by 0x428327: rpl_re_compile_pattern (regcomp.c:217)
==233608==    by 0x405084: regex_compile (dfasearch.c:164)
==233608==    by 0x4053CA: GEAcompile (dfasearch.c:265)
==233608==    by 0x404427: main (grep.c:2975)
==233608==
==233608== 48 bytes in 1 blocks are definitely lost in loss record 11 of 25
==233608==    at 0x484486F: malloc (vg_replace_malloc.c:381)
==233608==    by 0x4275FC: analyze (regcomp.c:1133)
==233608==    by 0x4275FC: re_compile_internal (regcomp.c:769)
==233608==    by 0x428327: rpl_re_compile_pattern (regcomp.c:217)
==233608==    by 0x405084: regex_compile (dfasearch.c:164)
==233608==    by 0x4053CA: GEAcompile (dfasearch.c:265)
==233608==    by 0x404427: main (grep.c:2975)
==233608==
==233608== 64 (48 direct, 16 indirect) bytes in 1 blocks are
definitely lost in loss record 12 of 25
==233608==    at 0x484486F: malloc (vg_replace_malloc.c:381)
==233608==    by 0x42760C: analyze (regcomp.c:1134)
==233608==    by 0x42760C: re_compile_internal (regcomp.c:769)
==233608==    by 0x428327: rpl_re_compile_pattern (regcomp.c:217)
==233608==    by 0x405084: regex_compile (dfasearch.c:164)
==233608==    by 0x4053CA: GEAcompile (dfasearch.c:265)
==233608==    by 0x404427: main (grep.c:2975)
==233608==
==233608== 128 bytes in 1 blocks are possibly lost in loss record 19 of 25
==233608==    at 0x48496AF: realloc (vg_replace_malloc.c:1437)
==233608==    by 0x42A2F8: xrealloc (xmalloc.c:65)
==233608==    by 0x42A2F8: xpalloc (xmalloc.c:270)
==233608==    by 0x405390: GEAcompile (dfasearch.c:258)
==233608==    by 0x404427: main (grep.c:2975)
==233608==
==233608== 192 (48 direct, 144 indirect) bytes in 1 blocks are
definitely lost in loss record 20 of 25
==233608==    at 0x4849464: calloc (vg_replace_malloc.c:1328)
==233608==    by 0x427186: init_dfa (regcomp.c:834)
==233608==    by 0x427186: re_compile_internal (regcomp.c:732)
==233608==    by 0x428327: rpl_re_compile_pattern (regcomp.c:217)
==233608==    by 0x405084: regex_compile (dfasearch.c:164)
==233608==    by 0x4053CA: GEAcompile (dfasearch.c:265)
==233608==    by 0x404427: main (grep.c:2975)
==233608==
==233608== LEAK SUMMARY:
==233608==    definitely lost: 192 bytes in 5 blocks
==233608==    indirectly lost: 160 bytes in 6 blocks
==233608==      possibly lost: 128 bytes in 1 blocks
==233608==    still reachable: 112,098 bytes in 15 blocks
==233608==         suppressed: 0 bytes in 0 blocks
==233608== Reachable blocks (those to which a pointer was found) are not shown.
==233608== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==233608==
==233608== For lists of detected and suppressed errors, rerun with: -s
==233608== ERROR SUMMARY: 6 errors from 6 contexts (suppressed: 0 from 0)

Sharing my current incomplete state, because I'm out of time for the moment.

regex_compile.diff
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