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From 32578afb817f20446d888326814b52a8f3d6c0fe Mon Sep 17 00:00:00 2001
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From: Simo Sorce <simo@redhat.com>
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Date: Thu, 26 Oct 2017 16:59:18 -0400
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Subject: [PATCH] Do not call gpm_grab_sock() twice
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In the gpm_get_ctx() call, we unnecessarily call gpm_grab_sock() which
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would cause the lock to be held by one thread and never released. We
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already call gpm_grab_sock() as the first thing after gpm_get_ctx() in
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gpm_make_call(), plus gpm_make_call() properly releases the socket
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once done.
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This corrects the deadlock fix in
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461a5fa9f91a2753ebeef6323a64239c35e2f250, which incorrectly released
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the lock we wanted to grab. This caused the socket to not be locked
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to our thread. Another thread could come along and change the global
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ctx while we were still using the socket from another thread, causing
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concurrency issues as only one request can be in flight on any given
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socket at the same time.
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In special cases where the "thread" uid/gid changes (like in
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rpc.gssd), we end up closing the socket while we are still waiting for
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an answer from the server, causing additional issues and confusion.
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[rharwood@redhat.com: squashed 2 commits; minor edits accordingly]
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Signed-off-by: Simo Sorce <simo@redhat.com>
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Reviewed-by: Robbie Harwood <rharwood@redhat.com>
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Merges: #218
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(cherry picked from commit 8590c5dbc6fa07d0c366df23b982a4b6b9ffc259)
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---
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proxy/src/client/gpm_common.c | 9 +++------
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1 file changed, 3 insertions(+), 6 deletions(-)
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diff --git a/proxy/src/client/gpm_common.c b/proxy/src/client/gpm_common.c
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index 69f4741..2133618 100644
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--- a/proxy/src/client/gpm_common.c
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+++ b/proxy/src/client/gpm_common.c
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@@ -152,7 +152,9 @@ static int gpm_grab_sock(struct gpm_ctx *gpmctx)
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ret = gpm_open_socket(gpmctx);
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}
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- pthread_mutex_unlock(&gpmctx->lock);
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+ if (ret) {
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+ pthread_mutex_unlock(&gpmctx->lock);
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+ }
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return ret;
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}
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@@ -304,11 +306,6 @@ static struct gpm_ctx *gpm_get_ctx(void)
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pthread_once(&gpm_init_once_control, gpm_init_once);
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- ret = gpm_grab_sock(&gpm_global_ctx);
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- if (ret) {
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- return NULL;
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- }
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-
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return &gpm_global_ctx;
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}
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