read_dts_node() registers shared interrupt handlers via devm_request_irq() with fman as dev_id. Two bugs exist in the current code: 1) Pre-init NULL dereference: at registration time fman is only partially initialized -- kzalloc_obj() zero-initializes all fields, so fman->cfg and fman->fpm_regs are NULL. The handlers check is_init_done(fman->cfg) to guard against incomplete init, but is_init_done(NULL) returns true (intended to mean cfg was freed after successful init), so the guard is bypassed and fpm_regs is dereferenced. If another device on the same shared IRQ line fires during the window between devm_request_irq() and fman_init(), the handler accesses NULL fpm_regs via ioread32be(), causing a crash. 2) Use-after-free on probe failure: fman is allocated with kzalloc_obj() (not devm), so on error paths in read_dts_node() (ioremap failure, of_platform_populate failure) and fman_config(), kfree(fman) is called while the devm IRQ handlers remain registered. The driver core's subsequent devres_release_all() frees the IRQ handlers, but during the window between kfree(fman) and devm_free_irq(), a shared-IRQ spurious firing will dereference the already-freed fman. A previous attempt to fix issue #1 with an irq_ready flag protected by READ_ONCE()/WRITE_ONCE() is insufficient on weakly-ordered architectures. READ_ONCE()/WRITE_ONCE() only prevent compiler optimization; they do not provide the memory ordering guarantees (e.g., smp_store_release/smp_load_acquire) needed to ensure that writes to register pointers are visible to the IRQ handler before it observes the flag as true. Fix both issues by moving devm_request_irq() out of read_dts_node() and into fman_probe(), after both fman_config() and fman_init() have completed. This eliminates both race windows: by the time the handlers are registered, all register pointers are initialized (preventing the NULL dereference), and since fman is never freed after this point, the use-after-free cannot occur either. Add an 'irq' field to struct fman_dts_params so that the primary IRQ number parsed in read_dts_node() is available to fman_probe(). This replaces the previous approach (irq_ready flag with READ_ONCE) and also supersedes the separate UAF fix patch ("fsl_fman: fix use-after-free on IRQF_SHARED handler after probe failure" v3), as moving IRQ registration after init resolves both issues in a single change. v2: - move devm_request_irq() to fman_probe() after init (replaces irq_ready + READ_ONCE approach from v1) - supersede the separate UAF fix patch (v3), as this patch resolves both issues in a single change Fixes: 414fd46e7762 ("fsl/fman: Add FMan support") Link: https://lore.kernel.org/netdev/20260626162323.GE1310988@horms.kernel.org/ Signed-off-by: ZhaoJinming --- drivers/net/ethernet/freescale/fman/fman.c | 52 +++++++++++++--------- drivers/net/ethernet/freescale/fman/fman.h | 1 + 2 files changed, 32 insertions(+), 21 deletions(-) diff --git a/drivers/net/ethernet/freescale/fman/fman.c b/drivers/net/ethernet/freescale/fman/fman.c index 299bab043175..6947f3bc7c87 100644 --- a/drivers/net/ethernet/freescale/fman/fman.c +++ b/drivers/net/ethernet/freescale/fman/fman.c @@ -2695,7 +2695,7 @@ static struct fman *read_dts_node(struct platform_device *of_dev) void __iomem *base_addr; struct resource *res; u32 val, range[2]; - int err, irq; + int err; struct clk *clk; u32 clk_rate; @@ -2717,7 +2717,7 @@ static struct fman *read_dts_node(struct platform_device *of_dev) err = platform_get_irq(of_dev, 0); if (err < 0) goto fman_node_put; - irq = err; + fman->dts_params.irq = err; /* Get the FM error interrupt */ err = platform_get_irq(of_dev, 1); @@ -2773,25 +2773,6 @@ static struct fman *read_dts_node(struct platform_device *of_dev) of_node_put(muram_node); - err = devm_request_irq(&of_dev->dev, irq, fman_irq, IRQF_SHARED, - "fman", fman); - if (err < 0) { - dev_err(&of_dev->dev, "%s: irq %d allocation failed (error = %d)\n", - __func__, irq, err); - goto fman_free; - } - - if (fman->dts_params.err_irq != 0) { - err = devm_request_irq(&of_dev->dev, fman->dts_params.err_irq, - fman_err_irq, IRQF_SHARED, - "fman-err", fman); - if (err < 0) { - dev_err(&of_dev->dev, "%s: irq %d allocation failed (error = %d)\n", - __func__, fman->dts_params.err_irq, err); - goto fman_free; - } - } - base_addr = devm_platform_get_and_ioremap_resource(of_dev, 0, &res); if (IS_ERR(base_addr)) { err = PTR_ERR(base_addr); @@ -2848,6 +2829,35 @@ static int fman_probe(struct platform_device *of_dev) return -EINVAL; } + /* Register IRQ handlers only after initialization is complete. + * This prevents two issues: + * 1) Pre-init NULL dereference: is_init_done(NULL) returns true, + * so a shared-IRQ spurious firing before fpm_regs is set would + * dereference NULL. + * 2) Use-after-free on probe failure: fman was kzalloc'd (not devm), + * so on error paths kfree(fman) ran before devm_free_irq, leaving + * a window where the handler could fire with a freed dev_id. + * By registering here, both problems are eliminated. + */ + err = devm_request_irq(dev, fman->dts_params.irq, fman_irq, + IRQF_SHARED, "fman", fman); + if (err < 0) { + dev_err(dev, "%s: irq %d allocation failed (error = %d)\n", + __func__, fman->dts_params.irq, err); + return err; + } + + if (fman->dts_params.err_irq != 0) { + err = devm_request_irq(dev, fman->dts_params.err_irq, + fman_err_irq, IRQF_SHARED, + "fman-err", fman); + if (err < 0) { + dev_err(dev, "%s: irq %d allocation failed (error = %d)\n", + __func__, fman->dts_params.err_irq, err); + return err; + } + } + if (fman->dts_params.err_irq == 0) { fman_set_exception(fman, FMAN_EX_DMA_BUS_ERROR, false); fman_set_exception(fman, FMAN_EX_DMA_READ_ECC, false); diff --git a/drivers/net/ethernet/freescale/fman/fman.h b/drivers/net/ethernet/freescale/fman/fman.h index 74eb62eba0d7..630d57c3144c 100644 --- a/drivers/net/ethernet/freescale/fman/fman.h +++ b/drivers/net/ethernet/freescale/fman/fman.h @@ -286,6 +286,7 @@ struct fman_dts_params { struct resource *res; /* FMan memory resource */ u8 id; /* FMan ID */ + int irq; /* FMan IRQ */ int err_irq; /* FMan Error IRQ */ u16 clk_freq; /* FMan clock freq (In Mhz) */ -- 2.20.1