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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/106503] "const char []" in local scope never initialized
Date: Tue, 02 Aug 2022 07:47:55 +0000	[thread overview]
Message-ID: <bug-106503-4-67ZkH6Ti5u@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106503-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106503

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> -fsanitize=address sometimes can detect this kind of problems at runtime.


Program returned: 1
=================================================================
==1==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7f9235600030
at pc 0x7f9237ebcc9b bp 0x7ffc8cccff60 sp 0x7ffc8cccf720
READ of size 3 at 0x7f9235600030 thread T0
    #0 0x7f9237ebcc9a 
(/opt/compiler-explorer/gcc-snapshot/lib64/libasan.so.8+0x4ac9a) (BuildId:
f4e296dda2fcdab4980780e7f32c752a3e412556)
    #1 0x7f9237ebcf37 in writev
(/opt/compiler-explorer/gcc-snapshot/lib64/libasan.so.8+0x4af37) (BuildId:
f4e296dda2fcdab4980780e7f32c752a3e412556)
    #2 0x401673 in main (/app/output.s+0x401673) (BuildId:
af556f86dec87e7467f73a633f83c822f3afe85a)
    #3 0x7f923790b0b2 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x240b2) (BuildId:
9fdb74e7b217d06c93172a8243f8547f947ee6d1)
    #4 0x4010ed in _start (/app/output.s+0x4010ed) (BuildId:
af556f86dec87e7467f73a633f83c822f3afe85a)

Address 0x7f9235600030 is located in stack of thread T0 at offset 48 in frame
    #0 0x4011b5 in main (/app/output.s+0x4011b5) (BuildId:
af556f86dec87e7467f73a633f83c822f3afe85a)

  This frame has 2 object(s):
    [48, 52) 'junk' (line 22) <== Memory access at offset 48 is inside this
variable
    [64, 384) 'wdata' (line 15)
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
(/opt/compiler-explorer/gcc-snapshot/lib64/libasan.so.8+0x4ac9a) (BuildId:
f4e296dda2fcdab4980780e7f32c752a3e412556) 
Shadow bytes around the buggy address:
  0x0ff2c6ab7fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff2c6ab7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff2c6ab7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff2c6ab7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff2c6ab7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0ff2c6ab8000: f1 f1 f1 f1 f1 f1[f8]f2 00 00 00 00 00 00 00 00
  0x0ff2c6ab8010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff2c6ab8020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff2c6ab8030: f3 f3 f3 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
  0x0ff2c6ab8040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff2c6ab8050: 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
==1==ABORTING
fooabcbaz

  parent reply	other threads:[~2022-08-02  7:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-02  7:31 [Bug c/106503] New: " eb at emlix dot com
2022-08-02  7:36 ` [Bug c/106503] " eb at emlix dot com
2022-08-02  7:37 ` pinskia at gcc dot gnu.org
2022-08-02  7:47 ` pinskia at gcc dot gnu.org [this message]
2022-08-02  9:08 ` eb at emlix dot com
2022-08-02  9:44 ` redi at gcc dot gnu.org
2022-08-02 10:01 ` redi at gcc dot gnu.org

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