b24d18aa74
It seems that all the list_*_rcu primitives are missing a memory barrier on the very first dereference. For example, #define list_for_each_rcu(pos, head) \ for (pos = (head)->next; prefetch(pos->next), pos != (head); \ pos = rcu_dereference(pos->next)) It will go something like: pos = (head)->next prefetch(pos->next) pos != (head) do stuff We're missing a barrier here. pos = rcu_dereference(pos->next) fetch pos->next barrier given by rcu_dereference(pos->next) store pos Without the missing barrier, the pos->next value may turn out to be stale. In fact, if "do stuff" were also dereferencing pos and relying on list_for_each_rcu to provide the barrier then it may also break. So here is a patch to make sure that we have a barrier for the first element in the list. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> |
||
|---|---|---|
| .. | ||
| acpi | ||
| asm-alpha | ||
| asm-arm | ||
| asm-arm26 | ||
| asm-cris | ||
| asm-frv | ||
| asm-generic | ||
| asm-h8300 | ||
| asm-i386 | ||
| asm-ia64 | ||
| asm-m32r | ||
| asm-m68k | ||
| asm-m68knommu | ||
| asm-mips | ||
| asm-parisc | ||
| asm-powerpc | ||
| asm-ppc | ||
| asm-ppc64 | ||
| asm-s390 | ||
| asm-sh | ||
| asm-sh64 | ||
| asm-sparc | ||
| asm-sparc64 | ||
| asm-um | ||
| asm-v850 | ||
| asm-x86_64 | ||
| asm-xtensa | ||
| linux | ||
| math-emu | ||
| media | ||
| mtd | ||
| net | ||
| pcmcia | ||
| rdma | ||
| rxrpc | ||
| scsi | ||
| sound | ||
| video | ||