c9e2fbd909
While debugging bit_spin_lock() hang, it was tracked down to gcc-4.4
misoptimization of non-inlined constant_test_bit() due to non-volatile
addr when 'const volatile unsigned long *addr' cast to 'unsigned long *'
with subsequent unconditional jump to pause (and not to the test) leading
to hang.
Compiling with gcc-4.3 or disabling CONFIG_OPTIMIZE_INLINING yields inlined
constant_test_bit() and correct jump, thus working around the kernel bug.
Other arches than asm-x86 may implement this slightly differently;
2.6.29 mitigates the misoptimization by changing the function prototype
(commit
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boot | ||
configs | ||
crypto | ||
ia32 | ||
include/asm | ||
kernel | ||
kvm | ||
lguest | ||
lib | ||
math-emu | ||
mm | ||
oprofile | ||
pci | ||
power | ||
tools | ||
vdso | ||
video | ||
xen | ||
.gitignore | ||
Kbuild | ||
Kconfig | ||
Kconfig.cpu | ||
Kconfig.debug | ||
Makefile | ||
Makefile_32.cpu |