Am 11.04.2017 um 11:45 schrieb Huang Rui:
On Tue, Apr 11, 2017 at 02:53:27PM +0800, Christian König wrote:
Am 11.04.2017 um 04:58 schrieb Huang Rui:
This patch fixes the case when buffer funcs is empty and bo evict is
executing. It must double check buffer funcs, otherwise, a NULL
pointer dereference kernel panic will be encountered.
BUG: unable to handle kernel NULL pointer dereference at 00000000000001a4
IP: [<ffffffffa067b6cd>] amdgpu_evict_flags+0x3d/0xf0 [amdgpu]
PGD 0
Oops: 0000 [#1] SMP
Modules linked in: amdgpu(OE) ttm drm_kms_helper drm i2c_algo_bit
fb_sys_fops syscopyarea sysfillrect sysimgblt fmem(OE) physmem_drv(OE)
rpcsec_gss_krb5 nfsv4 nfs fscache intel_rapl x86_pkg_temp_thermal
intel_powerclamp snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic
kvm_intel snd_hda_intel snd_hda_codec kvm snd_hda_core joydev eeepc_wmi
asus_wmi sparse_keymap snd_hwdep snd_pcm irqbypass crct10dif_pclmul
snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq crc32_pclmul snd_seq_device
ghash_clmulni_intel aesni_intel aes_x86_64 snd_timer lrw gf128mul mei_me snd
glue_helper ablk_helper cryptd tpm_infineon mei lpc_ich serio_raw soundcore
shpchp mac_hid nfsd auth_rpcgss nfs_acl lockd grace coretemp sunrpc parport_pc
ppdev lp parport autofs4 hid_generic mxm_wmi r8169 usbhid ahci
psmouse libahci nvme mii hid nvme_core wmi video
CPU: 3 PID: 1627 Comm: kworker/u8:17 Tainted: G OE 4.9.0-custom
#1
Hardware name: ASUS All Series/Z87-A, BIOS 1802 01/28/2014
Workqueue: events_unbound async_run_entry_fn
task: ffff88021e7057c0 task.stack: ffffc9000262c000
RIP: 0010:[<ffffffffa067b6cd>] [<ffffffffa067b6cd>]
amdgpu_evict_flags+0x3d/0xf0 [amdgpu]
RSP: 0018:ffffc9000262fb30 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88021e8a5858 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffc9000262fb58 RDI: ffff88021e8a5800
RBP: ffffc9000262fb48 R08: 0000000000000000 R09: ffff88021e8a5814
R10: 000000001def8f01 R11: ffff88021def8c80 R12: ffffc9000262fb58
R13: ffff88021d2b1990 R14: 0000000000000000 R15: ffff88021e8a5858
FS: 0000000000000000(0000) GS:ffff88022ed80000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000001a4 CR3: 0000000001c07000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Can we have the full stack trace please?
Eviction should never occur before the buffer funcs are initialized, so
that patch just papers over some kind of race condition on startup as
far as I can see.
If we set ip_block_mask=0xff, sdma ip won't enable it. So funcs_ring is
NULL at that time. Though it is a corner case, but we don't also expect it
hang with kernel panic. I met it when I was debugging S3.
Good point, you should mention that in the commit message.
With that fixed the patch is Reviewed-by: Christian König
<[email protected]>.
But I think there are a couple of more cases like this you might need to
fix to work with the SDMA disabled.
Regards,
Christian.
Thanks,
Rui
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