The patch titled
gcc-4.6: printk: use stable variable to dump kmsg buffer
has been added to the -mm tree. Its filename is
gcc-46-printk-use-stable-variable-to-dump-kmsg-buffer.patch
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------------------------------------------------------
Subject: gcc-4.6: printk: use stable variable to dump kmsg buffer
From: Andi Kleen <andi@xxxxxxxxxxxxxx>
kmsg_dump takes care to sample the global variables
inside a spinlock, but then goes on to use the same
variables outside the spinlock region too.
Use the correct variable. This will make the race
window smaller.
Found by gcc 4.6's new warnings.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/printk.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff -puN kernel/printk.c~gcc-46-printk-use-stable-variable-to-dump-kmsg-buffer kernel/printk.c
--- a/kernel/printk.c~gcc-46-printk-use-stable-variable-to-dump-kmsg-buffer
+++ a/kernel/printk.c
@@ -1546,9 +1546,9 @@ void kmsg_dump(enum kmsg_dump_reason rea
chars = logged_chars;
spin_unlock_irqrestore(&logbuf_lock, flags);
- if (logged_chars > end) {
- s1 = log_buf + log_buf_len - logged_chars + end;
- l1 = logged_chars - end;
+ if (chars > end) {
+ s1 = log_buf + log_buf_len - chars + end;
+ l1 = chars - end;
s2 = log_buf;
l2 = end;
@@ -1556,8 +1556,8 @@ void kmsg_dump(enum kmsg_dump_reason rea
s1 = "";
l1 = 0;
- s2 = log_buf + end - logged_chars;
- l2 = logged_chars;
+ s2 = log_buf + end - chars;
+ l2 = chars;
}
if (!spin_trylock_irqsave(&dump_list_lock, flags)) {
_
Patches currently in -mm which might be from andi@xxxxxxxxxxxxxx are
linux-next.patch
percpu-online-cpu-before-memory-failed-in-pcpu_alloc_pages.patch
modpost-support-objects-with-more-than-64k-sections.patch
kernelh-add-hw_err-printk-prefix-for-hardware-error-logging.patch
x86-use-hw_err-in-mce-handler.patch
gcc-46-irq-move-alloc_desk_mask-variables-inside-ifdef.patch
gcc-46-x86-avoid-unused-by-set-variables-in-rdmsr.patch
gcc-46-pagemap-avoid-unused-but-set-variable.patch
gcc-46-perf-fix-set-but-unused-variables-in-perf.patch
gcc-46-x86-fix-set-but-not-read-variables.patch
gcc-46-kgdb-remove-set-but-unused-newpc.patch
gcc-46-printk-use-stable-variable-to-dump-kmsg-buffer.patch
gcc-46-btrfs-clean-up-unused-variables-bugs.patch
gcc-46-btrfs-clean-up-unused-variables-nonbugs.patch
gcc-46-nfsd-fix-initialized-but-not-read-warnings.patch
gcc-46-acpi-fix-unused-but-set-variables-in-acpi.patch
gcc-46-mm-fix-unused-but-set-warnings.patch
gcc-46-kernel-fix-unused-but-set-warnings.patch
gcc-46-block-fix-unused-but-set-variables-in-blk-merge.patch
gcc-46-fs-fix-unused-but-set-warnings.patch
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