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author卜部昌平 <shyouhei@ruby-lang.org>2019-10-03 12:26:41 +0900
committer卜部昌平 <shyouhei@ruby-lang.org>2019-10-03 12:45:24 +0900
commiteb92159d72fc711387f7e17ffbaca1678f23fd47 (patch)
tree13c5177b80fbd50c7113eee5aca5158652f24f1b /insns.def
parentef697388becedf36966a2edcdcf88baca342b9e2 (diff)
downloadruby-eb92159d72fc711387f7e17ffbaca1678f23fd47.tar.gz
Revert https://github.com/ruby/ruby/pull/2486
This reverts commits: 10d6a3aca7 8ba48c1b85 fba8627dc1 dd883de5ba 6c6a25feca 167e6b48f1 7cb96d41a5 3207979278 595b3c4fdd 1521f7cf89 c11c5e69ac cf33608203 3632a812c0 f56506be0d 86427a3219 . The reason for the revert is that we observe ABA problem around inline method cache. When a cache misshits, we search for a method entry. And if the entry is identical to what was cached before, we reuse the cache. But the commits we are reverting here introduced situations where a method entry is freed, then the identical memory region is used for another method entry. An inline method cache cannot detect that ABA. Here is a code that reproduce such situation: ```ruby require 'prime' class << Integer alias org_sqrt sqrt def sqrt(n) raise end GC.stress = true Prime.each(7*37){} rescue nil # <- Here we populate CC class << Object.new; end # These adjacent remove-then-alias maneuver # frees a method entry, then immediately # reuses it for another. remove_method :sqrt alias sqrt org_sqrt end Prime.each(7*37).to_a # <- SEGV ```
Diffstat (limited to 'insns.def')
-rw-r--r--insns.def2
1 files changed, 1 insertions, 1 deletions
diff --git a/insns.def b/insns.def
index e3edc5e29f..f365106e2c 100644
--- a/insns.def
+++ b/insns.def
@@ -911,7 +911,7 @@ invokeblock
// attr rb_snum_t sp_inc = sp_inc_of_invokeblock(ci);
{
static struct rb_call_cache cc = {
- 0, 0, NULL, vm_invokeblock_i,
+ 0, 0, NULL, NULL, vm_invokeblock_i,
};
VALUE bh = VM_BLOCK_HANDLER_NONE;