63 lines
2.0 KiB
Diff
63 lines
2.0 KiB
Diff
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From a352f979545723054b0a74862a56dc53b1be93fb Mon Sep 17 00:00:00 2001
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From: Olivier Fourdan <ofourdan@redhat.com>
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Date: Tue, 8 Jan 2019 12:48:53 +0100
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Subject: [PATCH xserver] xwayland: handle case without any crtc
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Xwayland creates and destroys the CRTC along with the Wayland outputs,
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so there is possibly a case where the number of CRTC drops to 0.
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However, `xwl_present_get_crtc()` always return `crtcs[0]` which is
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invalid when `numCrtcs` is 0.
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That leads to crash if a client queries the Present capabilities when
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there is no CRTC, the backtrace looks like:
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#0 raise() from libc.so
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#1 abort() from libc.so
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#2 OsAbort() at utils.c:1350
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#3 AbortServer() at log.c:879
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#4 FatalError() at log.c:1017
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#5 OsSigHandler() at osinit.c:156
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#6 OsSigHandler() at osinit.c:110
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#7 <signal handler called>
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#8 main_arena() from libc.so
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#9 proc_present_query_capabilities() at present_request.c:236
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#10 Dispatch() at dispatch.c:478
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#11 dix_main() at main.c:276
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To avoid returning an invalid pointer (`crtcs[0]`) in that case, simply
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check for `numCrtcs` being 0 and return `NULL` in that case.
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Thanks to Michel Dänzer <michel.daenzer@amd.com> for pointing this as a
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possible cause of the crash.
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Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
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Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
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Bugzilla: https://bugzilla.redhat.com/1609181
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(cherry picked from commit e8295c50209f2963fa2823e8de7e8363a38cd2d1)
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---
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hw/xwayland/xwayland-present.c | 4 ++++
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1 file changed, 4 insertions(+)
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diff --git a/hw/xwayland/xwayland-present.c b/hw/xwayland/xwayland-present.c
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index 980034db4..74fe84672 100644
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--- a/hw/xwayland/xwayland-present.c
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+++ b/hw/xwayland/xwayland-present.c
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@@ -323,6 +323,10 @@ xwl_present_get_crtc(WindowPtr present_window)
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return NULL;
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rr_private = rrGetScrPriv(present_window->drawable.pScreen);
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+
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+ if (rr_private->numCrtcs == 0)
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+ return NULL;
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+
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return rr_private->crtcs[0];
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}
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--
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2.20.1
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