Zack Rusin <zack.rusin@xxxxxxxxxxxx> writes:
Hello Zack,
> Switch to a new plane state requires unreferencing of all held surfaces.
> In the work required for mob cursors the mapped surfaces started being
> cached but the variable indicating whether the surface is currently
> mapped was not being reset. This leads to crashes as the duplicated
> state, incorrectly, indicates the that surface is mapped even when
> no surface is present. That's because after unreferencing the surface
> it's perfectly possible for the plane to be backed by a bo instead of a
> surface.
>
> Reset the surface mapped flag when unreferencing the plane state surface
> to fix null derefs in cleanup. Fixes crashes in KDE KWin 6.0 on Wayland:
>
> Oops: 0000 [#1] PREEMPT SMP PTI
> CPU: 4 PID: 2533 Comm: kwin_wayland Not tainted 6.7.0-rc3-vmwgfx #2
> Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
> RIP: 0010:vmw_du_cursor_plane_cleanup_fb+0x124/0x140 [vmwgfx]
> Code: 00 00 00 75 3a 48 83 c4 10 5b 5d c3 cc cc cc cc 48 8b b3 a8 00 00 00 48 c7 c7 99 90 43 c0 e8 93 c5 db ca 48 8b 83 a8 00 00 00 <48> 8b 78 28 e8 e3 f>
> RSP: 0018:ffffb6b98216fa80 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffff969d84cdcb00 RCX: 0000000000000027
> RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff969e75f21600
> RBP: ffff969d4143dc50 R08: 0000000000000000 R09: ffffb6b98216f920
> R10: 0000000000000003 R11: ffff969e7feb3b10 R12: 0000000000000000
> R13: 0000000000000000 R14: 000000000000027b R15: ffff969d49c9fc00
> FS: 00007f1e8f1b4180(0000) GS:ffff969e75f00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000028 CR3: 0000000104006004 CR4: 00000000003706f0
> Call Trace:
> <TASK>
> ? __die+0x23/0x70
> ? page_fault_oops+0x171/0x4e0
> ? exc_page_fault+0x7f/0x180
> ? asm_exc_page_fault+0x26/0x30
> ? vmw_du_cursor_plane_cleanup_fb+0x124/0x140 [vmwgfx]
> drm_atomic_helper_cleanup_planes+0x9b/0xc0
> commit_tail+0xd1/0x130
> drm_atomic_helper_commit+0x11a/0x140
> drm_atomic_commit+0x97/0xd0
> ? __pfx___drm_printfn_info+0x10/0x10
> drm_atomic_helper_update_plane+0xf5/0x160
> drm_mode_cursor_universal+0x10e/0x270
> drm_mode_cursor_common+0x102/0x230
> ? __pfx_drm_mode_cursor2_ioctl+0x10/0x10
> drm_ioctl_kernel+0xb2/0x110
> drm_ioctl+0x26d/0x4b0
> ? __pfx_drm_mode_cursor2_ioctl+0x10/0x10
> ? __pfx_drm_ioctl+0x10/0x10
> vmw_generic_ioctl+0xa4/0x110 [vmwgfx]
> __x64_sys_ioctl+0x94/0xd0
> do_syscall_64+0x61/0xe0
> ? __x64_sys_ioctl+0xaf/0xd0
> ? syscall_exit_to_user_mode+0x2b/0x40
> ? do_syscall_64+0x70/0xe0
> ? __x64_sys_ioctl+0xaf/0xd0
> ? syscall_exit_to_user_mode+0x2b/0x40
> ? do_syscall_64+0x70/0xe0
> ? exc_page_fault+0x7f/0x180
> entry_SYSCALL_64_after_hwframe+0x6e/0x76
> RIP: 0033:0x7f1e93f279ed
> Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff f>
> RSP: 002b:00007ffca0faf600 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 000055db876ed2c0 RCX: 00007f1e93f279ed
> RDX: 00007ffca0faf6c0 RSI: 00000000c02464bb RDI: 0000000000000015
> RBP: 00007ffca0faf650 R08: 000055db87184010 R09: 0000000000000007
> R10: 000055db886471a0 R11: 0000000000000246 R12: 00007ffca0faf6c0
> R13: 00000000c02464bb R14: 0000000000000015 R15: 00007ffca0faf790
> </TASK>
> Modules linked in: snd_seq_dummy snd_hrtimer nf_conntrack_netbios_ns nf_conntrack_broadcast nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_ine>
> CR2: 0000000000000028
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:vmw_du_cursor_plane_cleanup_fb+0x124/0x140 [vmwgfx]
> Code: 00 00 00 75 3a 48 83 c4 10 5b 5d c3 cc cc cc cc 48 8b b3 a8 00 00 00 48 c7 c7 99 90 43 c0 e8 93 c5 db ca 48 8b 83 a8 00 00 00 <48> 8b 78 28 e8 e3 f>
> RSP: 0018:ffffb6b98216fa80 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffff969d84cdcb00 RCX: 0000000000000027
> RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff969e75f21600
> RBP: ffff969d4143dc50 R08: 0000000000000000 R09: ffffb6b98216f920
> R10: 0000000000000003 R11: ffff969e7feb3b10 R12: 0000000000000000
> R13: 0000000000000000 R14: 000000000000027b R15: ffff969d49c9fc00
> FS: 00007f1e8f1b4180(0000) GS:ffff969e75f00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000028 CR3: 0000000104006004 CR4: 00000000003706f0
>
> Signed-off-by: Zack Rusin <zack.rusin@xxxxxxxxxxxx>
> Fixes: 485d98d472d5 ("drm/vmwgfx: Add support for CursorMob and CursorBypass 4")
> Reported-by: Stefan Hoffmeister <stefan.hoffmeister@xxxxxxxxx>
> Closes: https://gitlab.freedesktop.org/drm/misc/-/issues/34
> Cc: Martin Krastev <martin.krastev@xxxxxxxxxxxx>
> Cc: Maaz Mombasawala <maaz.mombasawala@xxxxxxxxxxxx>
> Cc: Ian Forbes <ian.forbes@xxxxxxxxxxxx>
> Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list@xxxxxxxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: <stable@xxxxxxxxxxxxxxx> # v5.19+
> ---
I'm not familiar with this driver but your explanation in the commit
message is very clear and from inspecting the code, the change looks
correct to me.
Acked-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
--
Best regards,
Javier Martinez Canillas
Core Platforms
Red Hat
