https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87702
--- Comment #9 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to Mihail Zenkov from comment #7) > http://www.knk.uwebweb.com/glibc-segfault-2.tar.xz > > I put full command line into exit.cmd and vfscanf.cmd. Hm, it looks that for the first case __GI_exit gets called with misaligned stack: Breakpoint 2, __GI_exit (status=1) at exit.c:138 138 exit.c: No such file or directory. (gdb) disass Dump of assembler code for function __GI_exit: => 0xf7e241c0 <+0>: call 0xf7f29629 <__x86.get_pc_thunk.ax> 0xf7e241c5 <+5>: add $0x1a5e3b,%eax 0xf7e241ca <+10>: sub $0xc,%esp 0xf7e241cd <+13>: lea 0x3fc(%eax),%eax 0xf7e241d3 <+19>: push $0x1 0xf7e241d5 <+21>: push $0x1 0xf7e241d7 <+23>: push %eax 0xf7e241d8 <+24>: pushl 0x1c(%esp) 0xf7e241dc <+28>: call 0xf7e23fa0 <__run_exit_handlers> End of assembler dump. (gdb) i r $sp sp 0xffffc424 0xffffc424 (gdb) up #1 0x0804cdbf in ?? () (gdb) i r $sp sp 0xffffc428 0xffffc428 Following this, __GI_exit calls __run_exit_handlers with misaligned stack: Breakpoint 1, __run_exit_handlers (status=1, listp=0xf7fca3fc <__exit_funcs>, run_list_atexit=true, run_dtors=true) at exit.c:40 40 in exit.c (gdb) disass Dump of assembler code for function __run_exit_handlers: => 0xf7e23fa0 <+0>: push %ebp 0xf7e23fa1 <+1>: push %edi 0xf7e23fa2 <+2>: call 0xf7f29631 <__x86.get_pc_thunk.bp> 0xf7e23fa7 <+7>: add $0x1a6059,%ebp 0xf7e23fad <+13>: push %esi 0xf7e23fae <+14>: push %ebx 0xf7e23faf <+15>: sub $0x2c,%esp ... (gdb) i r $sp sp 0xffffc404 0xffffc404 (gdb) up #1 0xf7e241e1 in __GI_exit (status=1) at exit.c:139 139 in exit.c (gdb) i r $sp sp 0xffffc408 0xffffc408 This is wrong, gcc assumes 16-byte aligned stack. It looks that busybox is at fault here, it shouldn't call __GI_exit with misaligned stack.
