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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/108552] Linux i386 kernel 5.14 memory corruption for pre_compound_page() when gcov is enabled
Date: Fri, 27 Jan 2023 12:51:10 +0000 [thread overview]
Message-ID: <bug-108552-4-CFRR82NJSJ@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108552-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108552
--- Comment #19 from Uroš Bizjak <ubizjak at gmail dot com> ---
Some further analysis:
pretmp_94 = __gcov0.prep_compound_page[7]; <--
_179 = pretmp_94 + 1; <--
ivtmp.1725_211 = (unsigned long long) _179;
_135 = (unsigned int) nr_pages_11;
_134 = _135 + 4294967294; <--
_132 = (unsigned long long) _134; <--
_89 = (unsigned long long) pretmp_94; <--
_76 = _89 + 2; <-
_19 = _76 + _132; <-
And the loop exit condition is:
# ivtmp.1725_77 = PHI <ivtmp.1725_69(9), ivtmp.1725_211(8)>
...
ivtmp.1725_69 = ivtmp.1725_77 + 1;
And the loop exit condition is:
if (_19 != ivtmp.1725_69)
So, both ivtmp and _19 are calculated from the value at
__gcov0.prep_compound_page. But as shown in Comment #15, we have two separate
reads from the location, the compiler assumes that the value there is
invariant, which is probably not the case.
next prev parent reply other threads:[~2023-01-27 12:51 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-26 8:00 [Bug c/108552] New: " feng.tang at intel dot com
2023-01-26 8:01 ` [Bug c/108552] " feng.tang at intel dot com
2023-01-26 8:02 ` [Bug target/108552] " pinskia at gcc dot gnu.org
2023-01-26 8:05 ` pinskia at gcc dot gnu.org
2023-01-26 8:13 ` feng.tang at intel dot com
2023-01-26 8:19 ` pinskia at gcc dot gnu.org
2023-01-26 11:35 ` feng.tang at intel dot com
2023-01-26 11:37 ` feng.tang at intel dot com
2023-01-26 11:39 ` feng.tang at intel dot com
2023-01-26 16:03 ` feng.tang at intel dot com
2023-01-26 16:07 ` feng.tang at intel dot com
2023-01-26 19:06 ` pinskia at gcc dot gnu.org
2023-01-26 19:22 ` torvalds@linux-foundation.org
2023-01-27 9:52 ` ubizjak at gmail dot com
2023-01-27 10:47 ` ubizjak at gmail dot com
2023-01-27 10:56 ` ubizjak at gmail dot com
2023-01-27 12:23 ` ubizjak at gmail dot com
2023-01-27 12:29 ` ubizjak at gmail dot com
2023-01-27 12:31 ` [Bug tree-optimization/108552] " ubizjak at gmail dot com
2023-01-27 12:51 ` ubizjak at gmail dot com [this message]
2023-01-27 12:52 ` ubizjak at gmail dot com
2023-01-27 13:17 ` jakub at gcc dot gnu.org
2023-01-27 13:40 ` ubizjak at gmail dot com
2023-01-27 14:14 ` jakub at gcc dot gnu.org
2023-01-27 14:59 ` rguenth at gcc dot gnu.org
2023-01-27 15:01 ` rguenth at gcc dot gnu.org
2023-01-27 15:13 ` rguenth at gcc dot gnu.org
2023-01-27 15:15 ` jakub at gcc dot gnu.org
2023-01-27 15:18 ` rguenth at gcc dot gnu.org
2023-01-27 15:20 ` jakub at gcc dot gnu.org
2023-01-27 17:00 ` torvalds@linux-foundation.org
2023-01-27 17:05 ` torvalds@linux-foundation.org
2023-01-27 17:15 ` torvalds@linux-foundation.org
2023-01-27 17:19 ` jakub at gcc dot gnu.org
2023-01-27 17:29 ` jakub at gcc dot gnu.org
2023-01-27 22:30 ` vmakarov at gcc dot gnu.org
2023-01-28 14:20 ` feng.tang at intel dot com
2023-01-28 14:27 ` feng.tang at intel dot com
2023-01-28 14:29 ` feng.tang at intel dot com
2023-01-28 23:40 ` hubicka at ucw dot cz
2023-01-29 10:08 ` jakub at gcc dot gnu.org
2023-01-30 7:05 ` rguenth at gcc dot gnu.org
2023-01-30 7:09 ` rguenth at gcc dot gnu.org
2023-01-30 8:06 ` torvalds@linux-foundation.org
2023-01-30 8:30 ` jakub at gcc dot gnu.org
2023-01-30 8:44 ` rguenth at gcc dot gnu.org
2023-01-30 8:46 ` rguenther at suse dot de
2023-01-30 18:54 ` torvalds@linux-foundation.org
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