linux-kernel - [PATCH] drm/amdgpu: fix amdgpu_ras_block_late

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Date:   Thu, 17 Feb 2022 07:38:42 -0800
From:   trix@...hat.com
To:     alexander.deucher@....com, christian.koenig@....com,
        Xinhui.Pan@....com, airlied@...ux.ie, daniel@...ll.ch,
        nathan@...nel.org, ndesaulniers@...gle.com, Hawking.Zhang@....com,
        john.clements@....com, tao.zhou1@....com, YiPeng.Chai@....com,
        luben.tuikov@....com, Stanley.Yang@....com, Dennis.Li@....com,
        mukul.joshi@....com, nirmoy.das@....com
Cc:     amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, llvm@...ts.linux.dev,
        Tom Rix <trix@...hat.com>
Subject: [PATCH] drm/amdgpu: fix amdgpu_ras_block_late_init error handler

From: Tom Rix <trix@...hat.com>

Clang build fails with
amdgpu_ras.c:2416:7: error: variable 'ras_obj' is used uninitialized
  whenever 'if' condition is true
  if (adev->in_suspend || amdgpu_in_reset(adev)) {
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

amdgpu_ras.c:2453:6: note: uninitialized use occurs here
 if (ras_obj->ras_cb)
     ^~~~~~~

There is a logic error in the error handler's labels.
ex/ The sysfs: is the last goto label in the normal code but
is the middle of error handler.  Rework the error handler.

cleanup: is the first error, so it's handler should be last.

interrupt: is the second error, it's handler is next.  interrupt:
handles the failure of amdgpu_ras_interrupt_add_hander() by
calling amdgpu_ras_interrupt_remove_handler().  This is wrong,
remove() assumes the interrupt has been setup, not torn down by
add().  Change the goto label to cleanup.

sysfs is the last error, it's handler should be first.  sysfs:
handles the failure of amdgpu_ras_sysfs_create() by calling
amdgpu_ras_sysfs_remove().  But when the create() fails there
is nothing added so there is nothing to remove.  This error
handler is not needed. Remove the error handler and change
goto label to interrupt.

Fixes: b293e891b057 ("drm/amdgpu: add helper function to do common ras_late_init/fini (v3)")
Signed-off-by: Tom Rix <trix@...hat.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
index b5cd21cb6e58..c5c8a666110f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
@@ -2432,12 +2432,12 @@ int amdgpu_ras_block_late_init(struct amdgpu_device *adev,
 	if (ras_obj->ras_cb) {
 		r = amdgpu_ras_interrupt_add_handler(adev, ras_block);
 		if (r)
-			goto interrupt;
+			goto cleanup;
 	}
 
 	r = amdgpu_ras_sysfs_create(adev, ras_block);
 	if (r)
-		goto sysfs;
+		goto interrupt;
 
 	/* Those are the cached values at init.
 	 */
@@ -2447,12 +2447,11 @@ int amdgpu_ras_block_late_init(struct amdgpu_device *adev,
 	}
 
 	return 0;
-cleanup:
-	amdgpu_ras_sysfs_remove(adev, ras_block);
-sysfs:
+
+interrupt:
 	if (ras_obj->ras_cb)
 		amdgpu_ras_interrupt_remove_handler(adev, ras_block);
-interrupt:
+cleanup:
 	amdgpu_ras_feature_enable(adev, ras_block, 0);
 	return r;
 }
-- 
2.26.3