xserver: Branch 'master'

[GitLab Mirror]

 randr/rrlease.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

New commits:
commit f467f85ca1f780d5c7cf3c20888e399708d761ac
Author: Mario Kleiner <mario.kleiner.de at gmail.com>
Date:   Mon Oct 18 08:14:04 2021 +0200

    Fix RandR leasing for more than 1 simultaneously active lease.
    
    Due to a switched order of parameters in the xorg_list_add()
    call inside ProcRRCreateLease(), adding a new lease for RandR
    output leasing does not actually add the new RRLeasePtr lease
    record to the list of existing leases for a X-Screen, but instead
    replaces the existing list with a new list that has the new lease
    as the only element, and probably leaks a bit of memory.
    
    Therefore the server "forgets" all active leases for a screen,
    except for the last added lease. If multiple leases are created
    in a session, then destruction of all leases but the last one
    will fail in many cases, e.g., during server shutdown in
    RRCloseScreen(), or resource destruction, e.g., in
    RRCrtcDestroyResource().
    
    Most importantly, it fails if a client simply close(fd)'es the
    DRM master descriptor to release a lease, quits, gets killed or
    crashes. In this case the kernel will destroy the lease and shut
    down the display output, then send a lease event via udev to the
    ddx, which e.g., in the modesetting-ddx will trigger a call to
    drmmode_validate_leases().
    
    That function is supposed to detect the released lease and tell
    the server to terminate the lease on the server side as well,
    via xf86CrtcLeaseTerminated(), but this doesn't happen for all
    the leases the server has forgotten. The end result is a dead
    video output, as the server won't reinitialize the crtc's
    corresponding to the terminated but forgotten lease.
    
    This bug was observed when using the amdvlk AMD OSS Vulkan
    driver and trying to lease multiple VKDisplay's, and also
    under Mesa radv, as both Mesa Vulkan/WSI/Display and amdvlk
    terminate leases by simply close()ing the lease fd, not by
    sending explicit RandR protocol requests to free leases.
    
    Leasing worked, but ending a session with multiple active
    leases ended in a lot of unpleasant darkness.
    
    Fixing the wrong argument order to xorg_list_add() fixes the
    problem. Tested on single-X-Screen and dual-X-Screen setups,
    with one, two or three active leases.
    
    Please merge this for the upcoming server 21.1 branch.
    Merging into server 1.20 would also make a lot of sense.
    
    Fixes: e4e3447603b5fd3a38a92c3f972396d1f81168ad
    Signed-off-by: Mario Kleiner <mario.kleiner.de at gmail.com>
    Cc: Keith Packard <keithp at keithp.com>

diff --git a/randr/rrlease.c b/randr/rrlease.c
index e25d9ca99..11ba96f24 100644
--- a/randr/rrlease.c
+++ b/randr/rrlease.c
@@ -295,7 +295,7 @@ ProcRRCreateLease(ClientPtr client)
     if (rc != Success)
         goto bail_lease;
 
-    xorg_list_add(&scr_priv->leases, &lease->list);
+    xorg_list_add(&lease->list, &scr_priv->leases);
 
     if (!AddResource(stuff->lid, RRLeaseType, lease)) {
         close(fd);