diff options
| author | Jesper Juhl <jj@chaosbits.net> | 2010-12-25 19:57:41 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-12-27 14:33:30 +0100 |
| commit | 5cdd2de0a76d0ac47f107c8a7b32d75d25768dc1 (patch) | |
| tree | 34b4834f0a377f571b050fd13abb4bc8a8da3821 /arch | |
| parent | eda4b716ea1f2a647a39cebae66b3fae4c4b80e4 (diff) | |
| download | lwn-5cdd2de0a76d0ac47f107c8a7b32d75d25768dc1.tar.gz lwn-5cdd2de0a76d0ac47f107c8a7b32d75d25768dc1.zip | |
x86/microcode: Fix double vfree() and remove redundant pointer checks before vfree()
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 <jj@chaosbits.net>
Acked-by: Tigran 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: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/microcode_intel.c | 16 |
1 files changed, 5 insertions, 11 deletions
diff --git a/arch/x86/kernel/microcode_intel.c b/arch/x86/kernel/microcode_intel.c index dcb65cc0a053..1a1b606d3e92 100644 --- a/arch/x86/kernel/microcode_intel.c +++ b/arch/x86/kernel/microcode_intel.c @@ -364,8 +364,7 @@ static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size, /* 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_microcode(int cpu, void *data, size_t size, 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_microcode(int cpu, void *data, size_t size, 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_microcode(int cpu, void *data, size_t size, 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", |