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From: Aleksandar Ristovski <aristovski@qnx.com>
To: gdb@sourceware.org
Subject: Frame lost after 'leave' and before 'ret' instruction on i386?
Date: Fri, 16 May 2008 15:32:00 -0000	[thread overview]
Message-ID: <482DA814.7030703@qnx.com> (raw)

Hello,

I noticed that after 'leave' asm instruction (and before 'ret') one frame will be lost (skipped).

For example:

(gdb) disassemble doSth
Dump of assembler code for function doSth:
0x080484f4 <doSth+0>:   push   %ebp
0x080484f5 <doSth+1>:   mov    %esp,%ebp
0x080484f7 <doSth+3>:   sub    $0x8,%esp
0x080484fa <doSth+6>:   sub    $0xc,%esp
0x080484fd <doSth+9>:   push   $0x8048570
0x08048502 <doSth+14>:  call   0x8048348 <printf@plt>
0x08048507 <doSth+19>:  add    $0x10,%esp
0x0804850a <doSth+22>:  leave
0x0804850b <doSth+23>:  ret
End of assembler dump.
(gdb) info registers
...
eip            0x804850b        0x804850b <doSth+23>
...
(gdb) bt
#0  0x080483c3 in doSth () at main.c:6
#1  0xb7ebffdc in __libc_start_main () from /lib/libc.so.6
#2  0x08048331 in _start ()

(note 'main' that really made the call is missing... e.g., just before "leave" was executed:
(gdb) bt
#0  doSth () at main.c:6
#1  0x080483da in main () at main.c:10
)

What happens is, we have restored the stack pointer but gdb is unaware of that fact and tries to unwind using already unwound value...

how is this supposed to work?


             reply	other threads:[~2008-05-16 15:32 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-16 15:32 Aleksandar Ristovski [this message]
2008-05-16 15:58 ` Daniel Jacobowitz
2008-05-16 16:02   ` Aleksandar Ristovski
2008-05-16 16:09     ` Daniel Jacobowitz
2008-05-22 14:29   ` Aleksandar Ristovski
2008-05-22 14:40     ` Aleksandar Ristovski
2008-05-22 14:50     ` Daniel Jacobowitz
2008-05-22 15:05       ` Aleksandar Ristovski
2008-05-22 16:00         ` Aleksandar Ristovski
2008-05-22 16:02         ` Daniel Jacobowitz
2008-05-23 15:19           ` Aleksandar Ristovski
2008-05-22 18:06             ` Aleksandar Ristovski
2008-05-23 17:11             ` Daniel Jacobowitz
2008-05-23 17:23         ` Michael Snyder
2008-05-26 23:08           ` Aleksandar Ristovski
2008-05-27 21:33             ` Aleksandar Ristovski
2008-05-29  6:21             ` Thiago Jung Bauermann
2008-05-29  6:22               ` Aleksandar Ristovski
2008-06-04 13:12             ` Aleksandar Ristovski
2008-06-05 20:12               ` Mark Kettenis
2008-05-16 17:24 ` Mark Kettenis
2008-05-16 17:28   ` Aleksandar Ristovski
2008-05-16 17:47     ` Daniel Jacobowitz
2008-05-16 17:48     ` Mark Kettenis

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