2.6.36-stable review patch. If anyone has any objections, please let us know.
------------------ From: Jesper Juhl <[email protected]> commit 5cdd2de0a76d0ac47f107c8a7b32d75d25768dc1 upstream. 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: Jesper Juhl <[email protected]> Acked-by: Tigran Aivazian <[email protected]> Cc: Shaohua Li <[email protected]> LKML-Reference: <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kernel/microcode_intel.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) --- a/arch/x86/kernel/microcode_intel.c +++ b/arch/x86/kernel/microcode_intel.c @@ -364,8 +364,7 @@ static enum ucode_state generic_load_mic /* For performance reasons, reuse mc area when possible */ if (!mc || mc_size > curr_mc_size) { - if (mc) - vfree(mc); + vfree(mc); mc = vmalloc(mc_size); if (!mc) break; @@ -374,13 +373,11 @@ static enum ucode_state generic_load_mic if (get_ucode_data(mc, ucode_ptr, mc_size) || microcode_sanity_check(mc) < 0) { - vfree(mc); break; } if (get_matching_microcode(&uci->cpu_sig, mc, new_rev)) { - if (new_mc) - vfree(new_mc); + vfree(new_mc); new_rev = mc_header.rev; new_mc = mc; mc = NULL; /* trigger new vmalloc */ @@ -390,12 +387,10 @@ static enum ucode_state generic_load_mic leftover -= mc_size; } - if (mc) - vfree(mc); + vfree(mc); if (leftover) { - if (new_mc) - vfree(new_mc); + vfree(new_mc); state = UCODE_ERROR; goto out; } @@ -405,8 +400,7 @@ static enum ucode_state generic_load_mic goto out; } - if (uci->mc) - vfree(uci->mc); + vfree(uci->mc); uci->mc = (struct microcode_intel *)new_mc; pr_debug("CPU%d found a matching microcode update with version 0x%x (current=0x%x)\n", _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
