Re: [PATCH] net: fman: fix clock and device node leak in probe error paths
From: Simon Horman <horms@kernel.org>
Date: 2026-06-19 12:18:19
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This is an AI-generated review of your patch. The human sending this email has considered the AI review valid, or at least plausible. Full review at: https://sashiko.dev Simon says: I think the first issue below does warrant being investigated within the context of this patch. The second one seems related to the intent of this patch, but I don't feel strongly about it needing to be fixed as part of this work. And the last one seems yet more weakly related. --- net: fman: fix clock and device node leak in probe error paths This patch aims to fix resource leaks in the error paths of read_dts_node(). It introduces a clk_put label to ensure the clock reference is properly released on probe failures.
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diff --git a/drivers/net/ethernet/freescale/fman/fman.c b/drivers/net/ethernet/freescale/fman/fman.c index 013273a2de32f..734cbe8efd7e3 100644 --- a/drivers/net/ethernet/freescale/fman/fman.c +++ b/drivers/net/ethernet/freescale/fman/fman.c
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@@ -2757,7 +2757,7 @@ static struct fman *read_dts_node(struct platform_device *of_dev) err = -EINVAL; dev_err(&of_dev->dev, "%s: could not find MURAM node\n", __func__); - goto fman_free; + goto clk_put; }
[Severity: High] Will this cause a double-free of the device node on error paths? In read_dts_node(), the call to of_find_matching_node() drops the reference on its "from" argument, which is fm_node: muram_node = of_find_matching_node(fm_node, fman_muram_match); By redirecting the error paths after this point to the clk_put label, the code falls through to fman_node_put and calls of_node_put(fm_node). Since of_find_matching_node() already consumed the reference, does this second put lead to a reference count underflow and use-after-free? [ ... ]
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@@ -2816,9 +2816,10 @@ static struct fman *read_dts_node(struct platform_device *of_dev) return fman;
[Severity: High] This isn't a bug introduced by this patch, but does this function leak the clock reference when returning successfully? While the patch correctly adds clk_put(clk) to the error paths, the success path shown above returns without releasing the reference acquired via of_clk_get(). Does the driver need to hold this reference throughout its lifetime, or should it be released here to prevent a memory leak during repeated driver binds and unbinds?
+clk_put: + clk_put(clk); fman_node_put: of_node_put(fm_node); -fman_free: kfree(fman); return ERR_PTR(err); }
[Severity: High] This is a pre-existing issue, but is it safe to manually free the fman structure here when devm-managed shared interrupts are still registered? The driver allocates fman using kzalloc_obj() and registers shared interrupt handlers using devm_request_irq(), passing fman as the dev_id. If initialization fails later in the function, the error path calls kfree(fman). However, the devm-managed interrupts are not unregistered until the probe function returns and devres cleanup runs. Because the interrupt is IRQF_SHARED, could another device trigger an interrupt during this window? If so, would the still-registered fman_irq handler attempt to access the already-freed fman structure?