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uma dbg: catch more corruption with atomics

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Use atomic testandset and testandclear to catch concurrent double free,
and to reduce the number of atomic operations.

Submitted by:	jeff
Reviewed by:	cem, kib, markj (all previous version)
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D22703
This commit is contained in:
Ryan Libby 2020-12-31 13:02:45 -08:00
parent ae4a8e5207
commit 942951ba46
1 changed files with 4 additions and 5 deletions
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9
sys/vm/uma_core.c
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@ -5392,10 +5392,10 @@ uma_dbg_alloc(uma_zone_t zone, uma_slab_t slab, void *item)
keg = zone->uz_keg;
freei = slab_item_index(slab, keg, item);
if (BIT_ISSET(keg->uk_ipers, freei, slab_dbg_bits(slab, keg)))
if (BIT_TEST_SET_ATOMIC(keg->uk_ipers, freei,
slab_dbg_bits(slab, keg)))
panic("Duplicate alloc of %p from zone %p(%s) slab %p(%d)",
item, zone, zone->uz_name, slab, freei);
BIT_SET_ATOMIC(keg->uk_ipers, freei, slab_dbg_bits(slab, keg));
}
/*
@ -5426,11 +5426,10 @@ uma_dbg_free(uma_zone_t zone, uma_slab_t slab, void *item)
panic("Unaligned free of %p from zone %p(%s) slab %p(%d)",
item, zone, zone->uz_name, slab, freei);
if (!BIT_ISSET(keg->uk_ipers, freei, slab_dbg_bits(slab, keg)))
if (!BIT_TEST_CLR_ATOMIC(keg->uk_ipers, freei,
slab_dbg_bits(slab, keg)))
panic("Duplicate free of %p from zone %p(%s) slab %p(%d)",
item, zone, zone->uz_name, slab, freei);
BIT_CLR_ATOMIC(keg->uk_ipers, freei, slab_dbg_bits(slab, keg));
}
#endif /* INVARIANTS */