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present: fix freed pointer access

Adam Jackson requested to merge ajax/xserver:patchwork-246007 into master

When a vblank has been marked as aborted, it's going to be free in the flip_notify function when stopped. We can't notify it after it's stopped because the pointer is invalid.

Valgrind backtrace:

==5331== Invalid read of size 8 ==5331== at 0x212B4D: present_vblank_notify (present_vblank.c:34) ==5331== by 0x21439B: present_wnmd_flip_notify (present_wnmd.c:194) ==5331== by 0x21439B: present_wnmd_event_notify (present_wnmd.c:228) ==5331== by 0x156216: xwl_present_sync_callback (xwayland-present.c:282) ==5331== by 0x6570FCD: ffi_call_unix64 (in /usr/lib/x86_64-linux-gnu/libffi.so.6.0.4) ==5331== by 0x657093E: ffi_call (in /usr/lib/x86_64-linux-gnu/libffi.so.6.0.4) ==5331== by 0x4DDB183: ??? (in /usr/lib/x86_64-linux-gnu/libwayland-client.so.0.3.0) ==5331== by 0x4DD79D8: ??? (in /usr/lib/x86_64-linux-gnu/libwayland-client.so.0.3.0) ==5331== by 0x4DD8EA3: wl_display_dispatch_queue_pending (in /usr/lib/x86_64-linux-gnu/libwayland-client.so.0.3.0) ==5331== by 0x14BCCA: xwl_read_events (xwayland.c:814) ==5331== by 0x2AC0D0: ospoll_wait (ospoll.c:651) ==5331== by 0x2A5322: WaitForSomething (WaitFor.c:208) ==5331== by 0x27574B: Dispatch (dispatch.c:421) ==5331== Address 0x1b44dc98 is 40 bytes inside a block of size 184 free'd ==5331== at 0x48369EB: free (vg_replace_malloc.c:530) ==5331== by 0x213B0A: present_wnmd_free_idle_vblanks (present_wnmd.c:118) ==5331== by 0x213B0A: present_wnmd_flips_stop (present_wnmd.c:161) ==5331== by 0x2143EF: present_wnmd_flip_notify (present_wnmd.c:192) ==5331== by 0x2143EF: present_wnmd_event_notify (present_wnmd.c:228) ==5331== by 0x156216: xwl_present_sync_callback (xwayland-present.c:282) ==5331== by 0x6570FCD: ffi_call_unix64 (in /usr/lib/x86_64-linux-gnu/libffi.so.6.0.4) ==5331== by 0x657093E: ffi_call (in /usr/lib/x86_64-linux-gnu/libffi.so.6.0.4) ==5331== by 0x4DDB183: ??? (in /usr/lib/x86_64-linux-gnu/libwayland-client.so.0.3.0) ==5331== by 0x4DD79D8: ??? (in /usr/lib/x86_64-linux-gnu/libwayland-client.so.0.3.0) ==5331== by 0x4DD8EA3: wl_display_dispatch_queue_pending (in /usr/lib/x86_64-linux-gnu/libwayland-client.so.0.3.0) ==5331== by 0x14BCCA: xwl_read_events (xwayland.c:814) ==5331== by 0x2AC0D0: ospoll_wait (ospoll.c:651) ==5331== by 0x2A5322: WaitForSomething (WaitFor.c:208) ==5331== Block was alloc'd at ==5331== at 0x48377D5: calloc (vg_replace_malloc.c:711) ==5331== by 0x212D9F: present_vblank_create (present_vblank.c:69) ==5331== by 0x214014: present_wnmd_pixmap (present_wnmd.c:610) ==5331== by 0x21576C: proc_present_pixmap (present_request.c:150) ==5331== by 0x27599D: Dispatch (dispatch.c:479) ==5331== by 0x279945: dix_main (main.c:276) ==5331== by 0x633AB16: (below main) (libc-start.c:310)

v2: Still notify aborted flips (Roman)

Signed-off-by: Lionel Landwerlin lionel.g.landwerlin@intel.com Reviewed-by: Daniel Stone daniels@collabora.com Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107314 Reviewed-by: Roman Gilg subdiff@gmail.com Tested-by: Roman Gilg subdiff@gmail.com

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