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From: "marxin at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/102769] wrong code at -O1 and above on x86_64-linux-gnu
Date: Fri, 15 Oct 2021 09:47:32 +0000	[thread overview]
Message-ID: <bug-102769-4-KJHA8B2fYZ@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102769-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102769

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID
                 CC|                            |marxin at gcc dot gnu.org

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
I think it's invalid code:

gcc-11 pr102769.c -g -fsanitize=address,undefined && ./a.out 
=================================================================
==27019==ERROR: AddressSanitizer: stack-use-after-scope on address
0x7fffffffdd00 at pc 0x000000400bfd bp 0x7fffffffdcd0 sp 0x7fffffffdcc8
READ of size 4 at 0x7fffffffdd00 thread T0
    #0 0x400bfc in main /home/marxin/Programming/testcases/pr102769.c:5
    #1 0x7ffff6a7553f in __libc_start_call_main
../sysdeps/nptl/libc_start_call_main.h:58
    #2 0x7ffff6a755eb in __libc_start_main_impl ../csu/libc-start.c:409
    #3 0x400a44 in _start (/home/marxin/Programming/testcases/a.out+0x400a44)

Address 0x7fffffffdd00 is located in stack of thread T0 at offset 32 in frame
    #0 0x400b15 in main /home/marxin/Programming/testcases/pr102769.c:2

  This frame has 2 object(s):
    [32, 36) 'h' (line 7) <== Memory access at offset 32 is inside this
variable
    [48, 128) 'g' (line 3)
HINT: this may be a false positive if your program uses some custom stack
unwind mechanism, swapcontext or vfork
      (longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-use-after-scope
/home/marxin/Programming/testcases/pr102769.c:5 in main
Shadow bytes around the buggy address:
  0x10007fff7b50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007fff7b60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007fff7b70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007fff7b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007fff7b90: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
=>0x10007fff7ba0:[f8]f2 00 00 00 00 00 00 00 00 00 00 f3 f3 f3 f3
  0x10007fff7bb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007fff7bc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007fff7bd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007fff7be0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x10007fff7bf0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc
==27019==ABORTING

  reply	other threads:[~2021-10-15  9:47 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-15  9:36 [Bug tree-optimization/102769] New: " zhendong.su at inf dot ethz.ch
2021-10-15  9:47 ` marxin at gcc dot gnu.org [this message]
2021-10-15 10:19 ` [Bug tree-optimization/102769] " zhendong.su at inf dot ethz.ch
2021-10-15 10:23 ` jakub at gcc dot gnu.org
2021-10-15 10:23 ` marxin at gcc dot gnu.org
2021-10-15 10:28 ` zhendong.su at inf dot ethz.ch
2021-10-15 10:33 ` marxin at gcc dot gnu.org
2021-10-15 10:38 ` zhendong.su at inf dot ethz.ch
2021-10-15 10:43 ` marxin at gcc dot gnu.org
2021-10-15 11:39 ` zhendong.su at inf dot ethz.ch
2021-10-15 11:42 ` jakub at gcc dot gnu.org
2021-10-15 15:17 ` zhendong.su at inf dot ethz.ch

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