Revision 55860d96ca59265d35427da0ee7d7f61e404f8e7 authored by Sebastian Andrzej Siewior on 26 June 2020, 03:29:55 UTC, committed by Linus Torvalds on 26 June 2020, 07:27:37 UTC
According to Christopher Lameter two fixes have been merged for the same problem. As far as I can tell, the code does not acquire the list_lock and invoke kmalloc(). list_slab_objects() misses an unlock (the counterpart to get_map()) and the memory allocated in free_partial() isn't used. Revert the mentioned commit. Link: http://lkml.kernel.org/r/20200618201234.795692-1-bigeasy@linutronix.de Fixes: aa456c7aebb14 ("slub: remove kmalloc under list_lock from list_slab_objects() V2") Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2006181501480.12014@www.lameter.com Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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hweight.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/export.h>
#include <linux/bitops.h>
#include <asm/types.h>
/**
* hweightN - returns the hamming weight of a N-bit word
* @x: the word to weigh
*
* The Hamming Weight of a number is the total number of bits set in it.
*/
unsigned int __sw_hweight32(unsigned int w)
{
#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
w -= (w >> 1) & 0x55555555;
w = (w & 0x33333333) + ((w >> 2) & 0x33333333);
w = (w + (w >> 4)) & 0x0f0f0f0f;
return (w * 0x01010101) >> 24;
#else
unsigned int res = w - ((w >> 1) & 0x55555555);
res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
res = (res + (res >> 4)) & 0x0F0F0F0F;
res = res + (res >> 8);
return (res + (res >> 16)) & 0x000000FF;
#endif
}
EXPORT_SYMBOL(__sw_hweight32);
unsigned int __sw_hweight16(unsigned int w)
{
unsigned int res = w - ((w >> 1) & 0x5555);
res = (res & 0x3333) + ((res >> 2) & 0x3333);
res = (res + (res >> 4)) & 0x0F0F;
return (res + (res >> 8)) & 0x00FF;
}
EXPORT_SYMBOL(__sw_hweight16);
unsigned int __sw_hweight8(unsigned int w)
{
unsigned int res = w - ((w >> 1) & 0x55);
res = (res & 0x33) + ((res >> 2) & 0x33);
return (res + (res >> 4)) & 0x0F;
}
EXPORT_SYMBOL(__sw_hweight8);
unsigned long __sw_hweight64(__u64 w)
{
#if BITS_PER_LONG == 32
return __sw_hweight32((unsigned int)(w >> 32)) +
__sw_hweight32((unsigned int)w);
#elif BITS_PER_LONG == 64
#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
w -= (w >> 1) & 0x5555555555555555ul;
w = (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul);
w = (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful;
return (w * 0x0101010101010101ul) >> 56;
#else
__u64 res = w - ((w >> 1) & 0x5555555555555555ul);
res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
res = res + (res >> 8);
res = res + (res >> 16);
return (res + (res >> 32)) & 0x00000000000000FFul;
#endif
#endif
}
EXPORT_SYMBOL(__sw_hweight64);
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