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dcd5fb82ff
Reference counting in amdgpu_dm_connector for amdgpu_dm_connector::dc_sink and amdgpu_dm_connector::dc_em_sink as well as in dc_link::local_sink seems to be out of shape. Thus make reference counting consistent for these members and just plain increment the reference count when the variable gets assigned and decrement when the pointer is set to zero or replaced. Also simplify reference counting in selected function sopes to be sure the reference is released in any case. In some cases add NULL pointer check before dereferencing. At a hand full of places a comment is placed to stat that the reference increment happened already somewhere else. This actually fixes the following kernel bug on my system when enabling display core in amdgpu. There are some more similar bug reports around, so it probably helps at more places. kernel BUG at mm/slub.c:294! invalid opcode: 0000 [#1] SMP PTI CPU: 9 PID: 1180 Comm: Xorg Not tainted 5.0.0-rc1+ #2 Hardware name: Supermicro X10DAi/X10DAI, BIOS 3.0a 02/05/2018 RIP: 0010:__slab_free+0x1e2/0x3d0 Code: 8b 54 24 30 48 89 4c 24 28 e8 da fb ff ff 4c 8b 54 24 28 85 c0 0f 85 67 fe ff ff 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <0f> 0b 49 3b 5c 24 28 75 ab 48 8b 44 24 30 49 89 4c 24 28 49 89 44 RSP: 0018:ffffb0978589fa90 EFLAGS: 00010246 RAX: ffff92f12806c400 RBX: 0000000080200019 RCX: ffff92f12806c400 RDX: ffff92f12806c400 RSI: ffffdd6421a01a00 RDI: ffff92ed2f406e80 RBP: ffffb0978589fb40 R08: 0000000000000001 R09: ffffffffc0ee4748 R10: ffff92f12806c400 R11: 0000000000000001 R12: ffffdd6421a01a00 R13: ffff92f12806c400 R14: ffff92ed2f406e80 R15: ffffdd6421a01a20 FS: 00007f4170be0ac0(0000) GS:ffff92ed2fb40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000562818aaa000 CR3: 000000045745a002 CR4: 00000000003606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? drm_dbg+0x87/0x90 [drm] dc_stream_release+0x28/0x50 [amdgpu] amdgpu_dm_connector_mode_valid+0xb4/0x1f0 [amdgpu] drm_helper_probe_single_connector_modes+0x492/0x6b0 [drm_kms_helper] drm_mode_getconnector+0x457/0x490 [drm] ? drm_connector_property_set_ioctl+0x60/0x60 [drm] drm_ioctl_kernel+0xa9/0xf0 [drm] drm_ioctl+0x201/0x3a0 [drm] ? drm_connector_property_set_ioctl+0x60/0x60 [drm] amdgpu_drm_ioctl+0x49/0x80 [amdgpu] do_vfs_ioctl+0xa4/0x630 ? __sys_recvmsg+0x83/0xa0 ksys_ioctl+0x60/0x90 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x5b/0x160 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f417110809b Code: 0f 1e fa 48 8b 05 ed bd 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d bd bd 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffdd8d1c268 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000562818a8ebc0 RCX: 00007f417110809b RDX: 00007ffdd8d1c2a0 RSI: 00000000c05064a7 RDI: 0000000000000012 RBP: 00007ffdd8d1c2a0 R08: 0000562819012280 R09: 0000000000000007 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000c05064a7 R13: 0000000000000012 R14: 0000000000000012 R15: 00007ffdd8d1c2a0 Modules linked in: nfsv4 dns_resolver nfs lockd grace fscache fuse vfat fat amdgpu intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul chash gpu_sched crc32_pclmul snd_hda_codec_realtek ghash_clmulni_intel amd_iommu_v2 iTCO_wdt iTCO_vendor_support ttm snd_hda_codec_generic snd_hda_codec_hdmi ledtrig_audio snd_hda_intel drm_kms_helper snd_hda_codec intel_cstate snd_hda_core drm snd_hwdep snd_seq snd_seq_device intel_uncore snd_pcm intel_rapl_perf snd_timer snd soundcore ioatdma pcspkr intel_wmi_thunderbolt mxm_wmi i2c_i801 lpc_ich pcc_cpufreq auth_rpcgss sunrpc igb crc32c_intel i2c_algo_bit dca wmi hid_cherry analog gameport joydev This patch is based on agd5f/drm-next-5.1-wip. This patch does not require all of that, but agd5f/drm-next-5.1-wip contains at least one more dc_sink counting fix that I could spot. Signed-off-by: Mathias Fröhlich <Mathias.Froehlich@web.de> Reviewed-by: Leo Li <sunpeng.li@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> |
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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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.