xserver: Branch 'master'

[GitLab Mirror]

 dix/resource.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

New commits:
commit 2efa6d659508346358a1ef27b2393e18843f66a3
Author: Olivier Fourdan <ofourdan at redhat.com>
Date:   Tue Jul 12 14:44:48 2022 +0200

    dix: Fix overzealous caching of ResourceClientBits()
    
    Commit c7311654 cached the value of ResourceClientBits(), but that value
    depends on the `MaxClients` value set either from the command line or
    from the configuration file.
    
    For the latter, a call to ResourceClientBits() is issued before the
    configuration file is read, meaning that the cached value is from the
    default, not from the maximum number of clients set in the configuration
    file.
    
    That obviously causes all sort of issues, including memory corruption
    and crashes of the Xserver when reaching the default limit value.
    
    To avoid that issue, also keep the LimitClient value, and recompute the
    ilog2() value if that changes, as on startup when the value is set from
    the the xorg.conf ServerFlags section.
    
    v2: Drop the `cache == 0` test
        Rename cache vars
    
    Fixes: c7311654 - dix: cache ResourceClientBits() value
    Closes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1310
    Signed-off-by: Olivier Fourdan <ofourdan at redhat.com>
    Reviewed-by: Adam Jackson <ajax at redhat.com>

diff --git a/dix/resource.c b/dix/resource.c
index 6c0be2e04..055e6934e 100644
--- a/dix/resource.c
+++ b/dix/resource.c
@@ -620,12 +620,15 @@ ilog2(int val)
 unsigned int
 ResourceClientBits(void)
 {
-    static unsigned int cached = 0;
+    static unsigned int cache_ilog2 = 0;
+    static unsigned int cache_limit = 0;
 
-    if (cached == 0)
-      cached = ilog2(LimitClients);
+    if (LimitClients != cache_limit) {
+        cache_limit = LimitClients;
+        cache_ilog2 = ilog2(LimitClients);
+    }
 
-    return cached;
+    return cache_ilog2;
 }
 
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