linux-kernel - [PATCH] habanalabs: fix double unlock on error in map_device

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Date:   Wed, 25 May 2022 15:25:06 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Oded Gabbay <ogabbay@...nel.org>, Ohad Sharabi <osharabi@...ana.ai>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Yuri Nudelman <ynudelman@...ana.ai>,
        Ofir Bitton <obitton@...ana.ai>,
        farah kassabri <fkassabri@...ana.ai>,
        Tomer Tayar <ttayar@...ana.ai>, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: [PATCH] habanalabs: fix double unlock on error in map_device_va()

If hl_mmu_prefetch_cache_range() fails then this code calls
mutex_unlock(&ctx->mmu_lock) when it's no longer holding the mutex.

Fixes: 9e495e24003e ("habanalabs: do MMU prefetch as deferred work")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
 drivers/misc/habanalabs/common/memory.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/habanalabs/common/memory.c b/drivers/misc/habanalabs/common/memory.c
index 663dd7e589d4..d5e6500f8a1f 100644
--- a/drivers/misc/habanalabs/common/memory.c
+++ b/drivers/misc/habanalabs/common/memory.c
@@ -1245,16 +1245,16 @@ static int map_device_va(struct hl_ctx *ctx, struct hl_mem_in *args, u64 *device
 	rc = map_phys_pg_pack(ctx, ret_vaddr, phys_pg_pack);
 	if (rc) {
 		dev_err(hdev->dev, "mapping page pack failed for handle %u\n", handle);
+		mutex_unlock(&ctx->mmu_lock);
 		goto map_err;
 	}
 
 	rc = hl_mmu_invalidate_cache_range(hdev, false, *vm_type | MMU_OP_SKIP_LOW_CACHE_INV,
 				ctx->asid, ret_vaddr, phys_pg_pack->total_size);
+	mutex_unlock(&ctx->mmu_lock);
 	if (rc)
 		goto map_err;
 
-	mutex_unlock(&ctx->mmu_lock);
-
 	/*
 	 * prefetch is done upon user's request. it is performed in WQ as and so can
 	 * be outside the MMU lock. the operation itself is already protected by the mmu lock
@@ -1283,8 +1283,6 @@ static int map_device_va(struct hl_ctx *ctx, struct hl_mem_in *args, u64 *device
 	return rc;
 
 map_err:
-	mutex_unlock(&ctx->mmu_lock);
-
 	if (add_va_block(hdev, va_range, ret_vaddr,
 				ret_vaddr + phys_pg_pack->total_size - 1))
 		dev_warn(hdev->dev,
-- 
2.35.1