412e85b605
Looks like a regression got introduced into nv50_mstc_atomic_check()
that somehow didn't get found until now. If userspace changes
crtc_state->active to false but leaves the CRTC enabled, we end up
calling drm_dp_atomic_find_vcpi_slots() using the PBN calculated in
asyh->dp.pbn. However, if the display is inactive we end up calculating
a PBN of 0, which inadvertently causes us to have an allocation of 0.
>From there, if userspace then disables the CRTC afterwards we end up
accidentally attempting to free the VCPI twice:
WARNING: CPU: 0 PID: 1484 at drivers/gpu/drm/drm_dp_mst_topology.c:3336
drm_dp_atomic_release_vcpi_slots+0x87/0xb0 [drm_kms_helper]
RIP: 0010:drm_dp_atomic_release_vcpi_slots+0x87/0xb0 [drm_kms_helper]
Call Trace:
drm_atomic_helper_check_modeset+0x3f3/0xa60 [drm_kms_helper]
? drm_atomic_check_only+0x43/0x780 [drm]
drm_atomic_helper_check+0x15/0x90 [drm_kms_helper]
nv50_disp_atomic_check+0x83/0x1d0 [nouveau]
drm_atomic_check_only+0x54d/0x780 [drm]
? drm_atomic_set_crtc_for_connector+0xec/0x100 [drm]
drm_atomic_commit+0x13/0x50 [drm]
drm_atomic_helper_set_config+0x81/0x90 [drm_kms_helper]
drm_mode_setcrtc+0x194/0x6a0 [drm]
? vprintk_emit+0x16a/0x230
? drm_ioctl+0x163/0x390 [drm]
? drm_mode_getcrtc+0x180/0x180 [drm]
drm_ioctl_kernel+0xaa/0xf0 [drm]
drm_ioctl+0x208/0x390 [drm]
? drm_mode_getcrtc+0x180/0x180 [drm]
nouveau_drm_ioctl+0x63/0xb0 [nouveau]
do_vfs_ioctl+0x405/0x660
? recalc_sigpending+0x17/0x50
? _copy_from_user+0x37/0x60
ksys_ioctl+0x5e/0x90
? exit_to_usermode_loop+0x92/0xe0
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x59/0x190
entry_SYSCALL_64_after_hwframe+0x44/0xa9
WARNING: CPU: 0 PID: 1484 at drivers/gpu/drm/drm_dp_mst_topology.c:3336
drm_dp_atomic_release_vcpi_slots+0x87/0xb0 [drm_kms_helper]
---[ end trace 4c395c0c51b1f88d ]---
[drm:drm_dp_atomic_release_vcpi_slots [drm_kms_helper]] *ERROR* no VCPI for
[MST PORT:00000000e288eb7d] found in mst state 000000008e642070
So, fix this by doing what we probably should have done from the start: only
call drm_dp_atomic_find_vcpi_slots() when crtc_state->mode_changed is set, so
that VCPI allocations remain for as long as the CRTC is enabled.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes:
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|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.