Add a check for the return value from platform_get_resource() call to be NULL.
If the passed device-tree contains a node for sram-device without a specified '<reg>' property value, for example:
sram: sram@5c0000000 { compatible = "nvidia,tegra186-sysram"; };
and the of_device_id[] '.data' element contains a sram_config* with '.map_only_reserved = true' property, we get the error:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.1.96 #1 Hardware name: linux,dummy-virt (DT) Call trace: sram_probe+0x134/0xd30 platform_probe+0x94/0x130 really_probe+0x124/0x580 __driver_probe_device+0xd0/0x1f0 driver_probe_device+0x50/0x1c0 __device_attach_driver+0x140/0x220 bus_for_each_drv+0xbc/0x130 __device_attach+0xec/0x2c0 device_initial_probe+0x24/0x40 bus_probe_device+0xd8/0xe0 device_add+0x67c/0xc80 of_device_add+0x58/0x80 of_platform_device_create_pdata+0xd0/0x1b0 of_platform_bus_create+0x27c/0x6f0 of_platform_populate+0xac/0x1d0 of_platform_default_populate_init+0x10c/0x130 do_one_initcall+0xdc/0x510 kernel_init_freeable+0x43c/0x4d8 kernel_init+0x2c/0x1e0 ret_from_fork+0x10/0x20
Fixes: 444b0111f3bc ("misc: sram: use devm_platform_ioremap_resource_wc()") Signed-off-by: Andrey Tsygunka aitsygunka@yandex.ru --- v3: Removed unnecessary 'unlikely()'. https://lore.kernel.org/lkml/2025041528-garment-senior-1c71@gregkh/ v2: Description changed based on comments from Markus Elfring at https://lore.kernel.org/linux-kernel/84969aba-67ba-4990-9065-6b55ce26ff92@we..., added tag 'Fixes', removed useless information from backtrace.
drivers/misc/sram.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c index e5069882457e..f308bfc56645 100644 --- a/drivers/misc/sram.c +++ b/drivers/misc/sram.c @@ -410,8 +410,13 @@ static int sram_probe(struct platform_device *pdev) if (IS_ERR(clk)) return PTR_ERR(clk);
- ret = sram_reserve_regions(sram, - platform_get_resource(pdev, IORESOURCE_MEM, 0)); + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "invalid resource\n"); + return -EINVAL; + } + + ret = sram_reserve_regions(sram, res); if (ret) return ret;