[AMD Public Use] Reviewed-by: Tao Zhou <tao.zhou1@xxxxxxx> > -----Original Message----- > From: Chen, Guchun <Guchun.Chen@xxxxxxx> > Sent: Thursday, August 13, 2020 2:45 PM > To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Zhang, Hawking > <Hawking.Zhang@xxxxxxx>; Li, Dennis <Dennis.Li@xxxxxxx>; Zhou1, Tao > <Tao.Zhou1@xxxxxxx>; Clements, John <John.Clements@xxxxxxx>; Deucher, > Alexander <Alexander.Deucher@xxxxxxx> > Cc: Chen, Guchun <Guchun.Chen@xxxxxxx> > Subject: [PATCH] drm/amdgpu: fix NULL pointer access issue when unloading > driver > > When unloading driver by "modprobe -r amdgpu", one NULL pointer > dereference bug occurs in ras debugfs releasing. The cause is the duplicated > debugfs_remove, as drm debugfs_root dir has been cleaned up already by > drm_minor_unregister. > > BUG: kernel NULL pointer dereference, address: 00000000000000a0 PGD 0 P4D > 0 > Oops: 0002 [#1] SMP PTI > CPU: 11 PID: 1526 Comm: modprobe Tainted: G OE 5.6.0-guchchen #1 > Hardware name: System manufacturer System Product Name/TUF Z370-PLUS > GAMING II, BIOS 0411 09/21/2018 > RIP: 0010:down_write+0x15/0x40 > Code: eb de e8 7e 17 72 ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 > 53 48 89 fb e8 92 > d8 ff ff 31 c0 ba 01 00 00 00 <f0> 48 0f b1 13 75 0f 65 48 8b 04 25 c0 8b 01 00 48 > 89 43 08 5b c3 > RSP: 0018:ffffb1590386fcd0 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: 00000000000000a0 RCX: 0000000000000000 > RDX: 0000000000000001 RSI: ffffffff85b2fcc2 RDI: 00000000000000a0 > RBP: ffffb1590386fd30 R08: ffffffff85b2fcc2 R09: 000000000002b3c0 > R10: ffff97a330618c40 R11: 00000000000005f6 R12: ffff97a3481beb40 > R13: 00000000000000a0 R14: ffff97a3481beb40 R15: 0000000000000000 > FS: 00007fb11a717540(0000) GS:ffff97a376cc0000(0000) > knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000000000a0 CR3: 00000004066d6006 CR4: 00000000003606e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call > Trace: > simple_recursive_removal+0x63/0x370 > ? debugfs_remove+0x60/0x60 > debugfs_remove+0x40/0x60 > amdgpu_ras_fini+0x82/0x230 [amdgpu] > ? __kernfs_remove.part.17+0x101/0x1f0 > ? kernfs_name_hash+0x12/0x80 > amdgpu_device_fini+0x1c0/0x580 [amdgpu] > amdgpu_driver_unload_kms+0x3e/0x70 [amdgpu] > amdgpu_pci_remove+0x36/0x60 [amdgpu] > pci_device_remove+0x3b/0xb0 > device_release_driver_internal+0xe5/0x1c0 > driver_detach+0x46/0x90 > bus_remove_driver+0x58/0xd0 > pci_unregister_driver+0x29/0x90 > amdgpu_exit+0x11/0x25 [amdgpu] > __x64_sys_delete_module+0x13d/0x210 > do_syscall_64+0x5f/0x250 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Signed-off-by: Guchun Chen <guchun.chen@xxxxxxx> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c > b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c > index 6170d7d28495..35d5bf9e6f6f 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c > @@ -1276,7 +1276,6 @@ void amdgpu_ras_debugfs_remove(struct > amdgpu_device *adev, > if (!obj || !obj->ent) > return; > > - debugfs_remove(obj->ent); > obj->ent = NULL; > put_obj(obj); > } > @@ -1290,7 +1289,6 @@ static void amdgpu_ras_debugfs_remove_all(struct > amdgpu_device *adev) > amdgpu_ras_debugfs_remove(adev, &obj->head); > } > > - debugfs_remove_recursive(con->dir); > con->dir = NULL; > } > /* debugfs end */ > -- > 2.17.1 _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
