https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119930
--- Comment #23 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
-fsanitize=address even gives an error at -O0 for the lambda object being used
after the scope ends:
Program returned: 1
=================================================================
==1==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7a81b44f0080
at pc 0x000000402067 bp 0x7ffd8fe34eb0 sp 0x7ffd8fe34ea8
READ of size 8 at 0x7a81b44f0080 thread T0
#0 0x000000402066 in
f()::{lambda()#2}::operator()(f()::{lambda()#2}::_ZZ1fvENKUlvE0_clEv.Frame*)
[clone .actor] (/app/output.s+0x402066) (BuildId:
a9cb4727b57885a9cd0f2668289a8d6085b7c729)
#1 0x000000402b1d in
std::__n4861::coroutine_handle<task::promise_type>::resume() const
(/app/output.s+0x402b1d) (BuildId: a9cb4727b57885a9cd0f2668289a8d6085b7c729)
#2 0x00000040262f in f() (/app/output.s+0x40262f) (BuildId:
a9cb4727b57885a9cd0f2668289a8d6085b7c729)
#3 0x000000402733 in main (/app/output.s+0x402733) (BuildId:
a9cb4727b57885a9cd0f2668289a8d6085b7c729)
#4 0x7e81b6429d8f (/lib/x86_64-linux-gnu/libc.so.6+0x29d8f) (BuildId:
095c7ba148aeca81668091f718047078d57efddb)
#5 0x7e81b6429e3f in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x29e3f) (BuildId:
095c7ba148aeca81668091f718047078d57efddb)
#6 0x0000004011a4 in _start (/app/output.s+0x4011a4) (BuildId:
a9cb4727b57885a9cd0f2668289a8d6085b7c729)
Address 0x7a81b44f0080 is located in stack of thread T0 at offset 128 in frame
#0 0x000000402506 in f() (/app/output.s+0x402506) (BuildId:
a9cb4727b57885a9cd0f2668289a8d6085b7c729)
This frame has 4 object(s):
[48, 49) '<unknown>'
[64, 72) 'coroutine_A' (line 63)
[96, 104) 'coroutine_B' (line 67)
[128, 136) '<unknown>' <== Memory access at offset 128 is inside this
variable
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 (/app/output.s+0x402066)
(BuildId: a9cb4727b57885a9cd0f2668289a8d6085b7c729) in
f()::{lambda()#2}::operator()(f()::{lambda()#2}::_ZZ1fvENKUlvE0_clEv.Frame*)
[clone .actor]
Shadow bytes around the buggy address:
0x7a81b44efe00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x7a81b44efe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x7a81b44eff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x7a81b44eff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x7a81b44f0000: f1 f1 f1 f1 f1 f1 f8 f2 00 f2 f2 f2 00 f2 f2 f2
=>0x7a81b44f0080:[f8]f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3 f3
0x7a81b44f0100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x7a81b44f0180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x7a81b44f0200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x7a81b44f0280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x7a81b44f0300: 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
