From d0ac63e462a71c267436d0bbc8fa638c39b9c69f Mon Sep 17 00:00:00 2001 From: Xavi Hernandez Date: Sun, 1 Mar 2020 19:49:04 +0100 Subject: cluster/afr: fix race when bricks come up The was a problem when self-heal was sending lookups at the same time that one of the bricks was coming up. In this case there was a chance that the number of 'up' bricks changes in the middle of sending the requests to subvolumes which caused a discrepancy in the expected number of replies and the actual number of sent requests. This discrepancy caused that AFR continued executing requests before all requests were complete. Eventually, the frame of the pending request was destroyed when the operation terminated, causing a use- after-free issue when the answer was finally received. In theory the same thing could happen in the reverse way, i.e. AFR tries to wait for more replies than sent requests, causing a hang. Change-Id: I7ed6108554ca379d532efb1a29b2de8085410b70 Signed-off-by: Xavi Hernandez Fixes: bz#1808875 --- xlators/cluster/afr/src/afr-self-heal-common.c | 4 +--- xlators/cluster/afr/src/afr-self-heal-name.c | 4 +++- xlators/cluster/afr/src/afr-self-heal.h | 7 +++++-- 3 files changed, 9 insertions(+), 6 deletions(-) (limited to 'xlators') diff --git a/xlators/cluster/afr/src/afr-self-heal-common.c b/xlators/cluster/afr/src/afr-self-heal-common.c index b2f0ef48011..fdec66340ba 100644 --- a/xlators/cluster/afr/src/afr-self-heal-common.c +++ b/xlators/cluster/afr/src/afr-self-heal-common.c @@ -1905,17 +1905,15 @@ int afr_selfheal_unlocked_discover(call_frame_t *frame, inode_t *inode, uuid_t gfid, struct afr_reply *replies) { - afr_private_t *priv = NULL; afr_local_t *local = NULL; dict_t *dict = NULL; - priv = frame->this->private; local = frame->local; if (local && local->xattr_req) dict = local->xattr_req; return afr_selfheal_unlocked_discover_on(frame, inode, gfid, replies, - priv->child_up, dict); + local->child_up, dict); } unsigned int diff --git a/xlators/cluster/afr/src/afr-self-heal-name.c b/xlators/cluster/afr/src/afr-self-heal-name.c index 7d4f2080ec3..dace07131cb 100644 --- a/xlators/cluster/afr/src/afr-self-heal-name.c +++ b/xlators/cluster/afr/src/afr-self-heal-name.c @@ -560,13 +560,15 @@ afr_selfheal_name_unlocked_inspect(call_frame_t *frame, xlator_t *this, struct afr_reply *replies = NULL; inode_t *inode = NULL; int first_idx = -1; + afr_local_t *local = NULL; priv = this->private; + local = frame->local; replies = alloca0(sizeof(*replies) * priv->child_count); inode = afr_selfheal_unlocked_lookup_on(frame, parent, bname, replies, - priv->child_up, NULL); + local->child_up, NULL); if (!inode) return -ENOMEM; diff --git a/xlators/cluster/afr/src/afr-self-heal.h b/xlators/cluster/afr/src/afr-self-heal.h index 9746860e36f..7a038fa7fe3 100644 --- a/xlators/cluster/afr/src/afr-self-heal.h +++ b/xlators/cluster/afr/src/afr-self-heal.h @@ -45,13 +45,16 @@ afr_local_t *__local = frame->local; \ afr_private_t *__priv = frame->this->private; \ int __i = 0; \ - int __count = AFR_COUNT(list, __priv->child_count); \ + int __count = 0; \ + unsigned char *__list = alloca(__priv->child_count); \ \ + memcpy(__list, list, sizeof(*__list) * __priv->child_count); \ + __count = AFR_COUNT(__list, __priv->child_count); \ __local->barrier.waitfor = __count; \ afr_local_replies_wipe(__local, __priv); \ \ for (__i = 0; __i < __priv->child_count; __i++) { \ - if (!list[__i]) \ + if (!__list[__i]) \ continue; \ STACK_WIND_COOKIE(frame, rfn, (void *)(long)__i, \ __priv->children[__i], \ -- cgit