[PATCH] drm/amdgpu: don't increase UMC RAS UE count if no new bad page

[Zhang, Hawking]

[AMD Official Use Only - General]

+                       /* if no new bad page is found, no need to increase ue count */
+                       if (ret == -EEXIST)
+                               err_data->ue_count = 0;

Returning EEXIST in such case is not reasonable. Might consider return a bool for amdgpu_ras_add_bad_pages: true means it does add some new bad page; false means it doesn't change anything.

Regards,
Hawking

-----Original Message-----
From: Zhou1, Tao <Tao.Zhou1 at amd.com>
Sent: Friday, February 10, 2023 16:45
To: amd-gfx at lists.freedesktop.org; Zhang, Hawking <Hawking.Zhang at amd.com>; Yang, Stanley <Stanley.Yang at amd.com>; Chai, Thomas <YiPeng.Chai at amd.com>; Li, Candice <Candice.Li at amd.com>
Cc: Zhou1, Tao <Tao.Zhou1 at amd.com>
Subject: [PATCH] drm/amdgpu: don't increase UMC RAS UE count if no new bad page

If a UMC bad page is reserved but not freed by an application, the application may trigger uncorrectable error repeatly by accessing the page.

Signed-off-by: Tao Zhou <tao.zhou1 at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 9 ++++++++-  drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c | 6 +++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
index e85c4689ce2c..eafe01a24349 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
@@ -2049,7 +2049,7 @@ int amdgpu_ras_add_bad_pages(struct amdgpu_device *adev,  {
        struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
        struct ras_err_handler_data *data;
-       int ret = 0;
+       int ret = 0, old_cnt;
        uint32_t i;

        if (!con || !con->eh_data || !bps || pages <= 0) @@ -2060,6 +2060,8 @@ int amdgpu_ras_add_bad_pages(struct amdgpu_device *adev,
        if (!data)
                goto out;

+       old_cnt = data->count;
+
        for (i = 0; i < pages; i++) {
                if (amdgpu_ras_check_bad_page_unlock(con,
                        bps[i].retired_page << AMDGPU_GPU_PAGE_SHIFT)) @@ -2079,6 +2081,11 @@ int amdgpu_ras_add_bad_pages(struct amdgpu_device *adev,
                data->count++;
                data->space_left--;
        }
+
+       /* all pages have been reserved before, no new bad page */
+       if (old_cnt == data->count)
+               ret = -EEXIST;
+
 out:
        mutex_unlock(&con->recovery_lock);

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c
index 1c7fcb4f2380..772c431e4065 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c
@@ -145,8 +145,12 @@ static int amdgpu_umc_do_page_retirement(struct amdgpu_device *adev,

                if ((amdgpu_bad_page_threshold != 0) &&
                        err_data->err_addr_cnt) {
-                       amdgpu_ras_add_bad_pages(adev, err_data->err_addr,
+                       ret = amdgpu_ras_add_bad_pages(adev, err_data->err_addr,
                                                err_data->err_addr_cnt);
+                       /* if no new bad page is found, no need to increase ue count */
+                       if (ret == -EEXIST)
+                               err_data->ue_count = 0;
+
                        amdgpu_ras_save_bad_pages(adev);

                        amdgpu_dpm_send_hbm_bad_pages_num(adev, con->eeprom_control.ras_num_recs);
--
2.35.1