• Jesper Juhl's avatar
    x86/microcode: Fix double vfree() and remove redundant pointer checks before vfree() · 5cdd2de0
    Jesper Juhl authored
    In arch/x86/kernel/microcode_intel.c::generic_load_microcode()
    we have  this:
    
    	while (leftover) {
    		...
    		if (get_ucode_data(mc, ucode_ptr, mc_size) ||
    		    microcode_sanity_check(mc) < 0) {
    			vfree(mc);
    			break;
    		}
    		...
    	}
    
    	if (mc)
    		vfree(mc);
    
    This will cause a double free of 'mc'. This patch fixes that by
    just  removing the vfree() call in the loop since 'mc' will be
    freed nicely just  after we break out of the loop.
    
    There's also a second change in the patch. I noticed a lot of
    checks for  pointers being NULL before passing them to vfree().
    That's completely  redundant since vfree() deals gracefully with
    being passed a NULL pointer.  Removing the redundant checks
    yields a nice size decrease for the object  file.
    
    Size before the patch:
       text    data     bss     dec     hex filename
       4578     240    1032    5850    16da arch/x86/kernel/microcode_intel.o
    Size after the patch:
       text    data     bss     dec     hex filename
       4489     240     984    5713    1651 arch/x86/kernel/microcode_intel.o
    Signed-off-by: default avatarJesper Juhl <jj@chaosbits.net>
    Acked-by: default avatarTigran Aivazian <tigran@aivazian.fsnet.co.uk>
    Cc: Shaohua Li <shaohua.li@intel.com>
    LKML-Reference: <alpine.LNX.2.00.1012251946100.10759@swampdragon.chaosbits.net>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    5cdd2de0
microcode_intel.c 13.4 KB