------- Comment #35 from phmagic at mail dot ru 2010-06-10 19:08 ------- Hello,
I just upgraded to gcc-4.4.3 (from Gentoo distribution) and recompiled the whole system (on x86). Then I had to discover the (as it turned to be, infamous) mozilla-firefox + zlib bug. I reported it to the distribution here: http://bugs.gentoo.org/show_bug.cgi?id=323431 As I learned later, everybody accounts for incoming misaligned stack to be the cause of the crashes. But what I see: inflate_table: .LFB45: .file 1 "inftrees.c" .loc 1 39 0 .LVL0: pushl %ebp ; stack misaligned to -4 .LCFI0: .loc 1 108 0 pxor %xmm0, %xmm0 .loc 1 39 0 movl %esp, %ebp ; $ebp % 16 = 4 .LCFI1: pushl %edi .LCFI2: pushl %esi .LCFI3: pushl %ebx .LCFI4: call .L101 .L101: popl %ebx addl $_GLOBAL_OFFSET_TABLE_+[.-.L101], %ebx subl $188, %esp .LCFI5: .loc 1 108 0 movdqa %xmm0, -56(%ebp) ; -56-4=60, 60%16=4 ; <snip> Even if the stack were 16 bytes aligned on the entry, the instruction in the last line would attempt an unaligned access and thus would fault. Please correct me, if I miscounted. My concern is: even with ABI which guarantees 16-byte aligned incoming stacks, gcc generates code which would segfault. -- phmagic at mail dot ru changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |phmagic at mail dot ru http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41156
