Am 2021-03-23 um 10:56 a.m. schrieb Alex Deucher:

Applied. Thanks!

Thanks. I thought we fixed this before by making the file write-only. But I guess that's not sufficient to stop root from reading it:

commit 2bdac179e217a0c0b548a8c60524977586621b19 Author: Felix Kuehling Felix.Kuehling@amd.com Date: Thu Dec 19 22:36:55 2019 -0500

drm/amdkfd: Fix permissions of hang_hws

Reading from /sys/kernel/debug/kfd/hang_hws would cause a kernel oops because we didn't implement a read callback. Set the permission to write-only to prevent that.

Signed-off-by: Felix Kuehling Felix.Kuehling@amd.com Reviewed-by: shaoyunl shaoyun.liu@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com

Now that we have a sensible message in the file, I guess we should officially make it readable again.

Regards,   Felix

Alex

On Sun, Mar 21, 2021 at 5:33 AM Qu Huang jinsdb@126.com wrote:

...

Here is the system crash log: [ 1272.884438] BUG: unable to handle kernel NULL pointer dereference at (null) [ 1272.884444] IP: [< (null)>] (null) [ 1272.884447] PGD 825b09067 PUD 8267c8067 PMD 0 [ 1272.884452] Oops: 0010 [#1] SMP [ 1272.884509] CPU: 13 PID: 3485 Comm: cat Kdump: loaded Tainted: G [ 1272.884515] task: ffff9a38dbd4d140 ti: ffff9a37cd3b8000 task.ti: ffff9a37cd3b8000 [ 1272.884517] RIP: 0010:[<0000000000000000>] [< (null)>] (null) [ 1272.884520] RSP: 0018:ffff9a37cd3bbe68 EFLAGS: 00010203 [ 1272.884522] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000014d5f [ 1272.884524] RDX: fffffffffffffff4 RSI: 0000000000000001 RDI: ffff9a38aca4d200 [ 1272.884526] RBP: ffff9a37cd3bbed0 R08: ffff9a38dcd5f1a0 R09: ffff9a31ffc07300 [ 1272.884527] R10: ffff9a31ffc07300 R11: ffffffffaddd5e9d R12: ffff9a38b4e0fb00 [ 1272.884529] R13: 0000000000000001 R14: ffff9a37cd3bbf18 R15: ffff9a38aca4d200 [ 1272.884532] FS: 00007feccaa67740(0000) GS:ffff9a38dcd40000(0000) knlGS:0000000000000000 [ 1272.884534] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1272.884536] CR2: 0000000000000000 CR3: 00000008267c0000 CR4: 00000000003407e0 [ 1272.884537] Call Trace: [ 1272.884544] [<ffffffffade68940>] ? seq_read+0x130/0x440 [ 1272.884548] [<ffffffffade40f8f>] vfs_read+0x9f/0x170 [ 1272.884552] [<ffffffffade41e4f>] SyS_read+0x7f/0xf0 [ 1272.884557] [<ffffffffae374ddb>] system_call_fastpath+0x22/0x27 [ 1272.884558] Code: Bad RIP value. [ 1272.884562] RIP [< (null)>] (null) [ 1272.884564] RSP <ffff9a37cd3bbe68> [ 1272.884566] CR2: 0000000000000000

Signed-off-by: Qu Huang jinsdb@126.com

drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c b/drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c index 511712c..673d5e3 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c @@ -33,6 +33,11 @@ static int kfd_debugfs_open(struct inode *inode, struct file *file)

    return single_open(file, show, NULL);

} +static int kfd_debugfs_hang_hws_read(struct seq_file *m, void *data) +{

•   seq_printf(m, "echo gpu_id > hang_hws\n");
  

•   return 0;
  

+}

static ssize_t kfd_debugfs_hang_hws_write(struct file *file, const char __user *user_buf, size_t size, loff_t *ppos) @@ -94,7 +99,7 @@ void kfd_debugfs_init(void) debugfs_create_file("rls", S_IFREG | 0444, debugfs_root, kfd_debugfs_rls_by_device, &kfd_debugfs_fops); debugfs_create_file("hang_hws", S_IFREG | 0200, debugfs_root,

•                       NULL, &kfd_debugfs_hang_hws_fops);
  

•                       kfd_debugfs_hang_hws_read, &kfd_debugfs_hang_hws_fops);
  

}

void kfd_debugfs_fini(void)

1.8.3.1

---

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