kernel/linux.git/drivers/gpio/gpiolib-shared.c, branch linux-7.1.y

gpio: shared: fix lockdep false positive by removing unneeded lock

2026-05-28T13:23:40+00:00

By the time gpio_device_teardown_shared() is called, the parent device is gone from the global list of GPIO devices and all outstanding SRCU read-side critical sections have completed. That means that no concurrent gpio_find_and_request() can call gpio_shared_add_proxy_lookup() for this device at this time. There's also no risk of the parent device being re-bound to the driver before the unbinding completes (including the child devices). Lockdep produces a false-positive report about a possible circular dependency as it doesn't know the ordering guarantee. Not taking the ref->lock in gpio_device_teardown_shared() silences it and is safe to do. Cc: stable@vger.kernel.org Fixes: ea513dd3c066 ("gpio: shared: make locking more fine-grained") Reviewed-by: Linus Walleij Link: https://patch.msgid.link/20260522-gpio-shared-deadlock-v1-2-76bca088f8c0@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

gpio: shared: fix deadlock on shared proxy's parent removal

2026-05-28T13:23:39+00:00

Commit 710abda58055 ("gpio: shared: call gpio_chip::of_xlate() if set") used the mutex embedded in struct gpio_shared_entry to protect the offset field which now can be modified after assignment. The critical section however is too wide and introduced a potential deadlock on the removal of the shared GPIO proxy's parent. Make the critical section shorter - only protect the offset when it's being read. While at it: mention the fact that the entry lock is now also used to protect against concurrent access to the offset field in the structure's documentation. Cc: stable@vger.kernel.org Fixes: 710abda58055 ("gpio: shared: call gpio_chip::of_xlate() if set") Reviewed-by: Linus Walleij Link: https://patch.msgid.link/20260522-gpio-shared-deadlock-v1-1-76bca088f8c0@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

gpio: shared: shorten the critical section in gpiochip_setup_shared()

2026-03-30T07:51:15+00:00

Commit 710abda58055 ("gpio: shared: call gpio_chip::of_xlate() if set") introduced a critical section around the adjustmenet of entry->offset. However this may cause a deadlock if we create the auxiliary shared proxy devices with this lock taken. We only need to protect entry->offset while it's read/written so shorten the critical section and release the lock before creating the proxy device as the field in question is no longer accessed at this point. Fixes: 710abda58055 ("gpio: shared: call gpio_chip::of_xlate() if set") Reported-by: Dmitry Baryshkov Link: https://patch.msgid.link/20260325-gpio-shared-deadlock-v1-1-e4e7a5319e95@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

gpio: shared: handle pins shared by child nodes of devices

2026-03-23T08:54:24+00:00

Shared GPIOs may be assigned to child nodes of device nodes which don't themselves bind to any struct device. We need to pass the firmware node that is the actual consumer to gpiolib-shared and compare against it instead of unconditionally using the fwnode of the consumer device. Fixes: a060b8c511ab ("gpiolib: implement low-level, shared GPIO support") Reported-by: Jon Hunter Closes: https://lore.kernel.org/all/921ba8ce-b18e-4a99-966d-c763d22081e2@nvidia.com/ Tested-by: Jon Hunter Acked-by: Jon Hunter Link: https://patch.msgid.link/20260318-gpio-shared-xlate-v2-2-0ce34c707e81@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

gpio: shared: call gpio_chip::of_xlate() if set

2026-03-23T08:54:24+00:00

OF-based GPIO controller drivers may provide a translation function that calculates the real chip offset from whatever devicetree sources provide. We need to take this into account in the shared GPIO management and call of_xlate() if it's provided and adjust the entry->offset we initially set when scanning the tree. To that end: modify the shared GPIO API to take the GPIO chip as argument on setup (to avoid having to rcu_dereference() it from the GPIO device) and protect the access to entry->offset with the existing lock. Fixes: a060b8c511ab ("gpiolib: implement low-level, shared GPIO support") Reported-by: Jon Hunter Closes: https://lore.kernel.org/all/921ba8ce-b18e-4a99-966d-c763d22081e2@nvidia.com/ Reviewed-by: Linus Walleij Tested-by: Jon Hunter Acked-by: Jon Hunter Link: https://patch.msgid.link/20260318-gpio-shared-xlate-v2-1-0ce34c707e81@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

gpio: shared: fix memory leaks

2026-02-23T10:01:13+00:00

On a Snapdragon X1 Elite laptop (Lenovo Yoga Slim 7x), kmemleak reports three sets of: unreferenced object 0xffff00080187f400 (size 1024): comm "swapper/0", pid 1, jiffies 4294667327 hex dump (first 32 bytes): 58 bd 70 01 08 00 ff ff 58 bd 70 01 08 00 ff ff X.p.....X.p..... 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................ backtrace (crc 1665d1f8): kmemleak_alloc+0xf4/0x12c __kmalloc_cache_noprof+0x370/0x49c gpio_shared_make_ref+0x70/0x16c gpio_shared_of_traverse+0x4e8/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_init+0x34/0x1c4 do_one_initcall+0x50/0x280 kernel_init_freeable+0x290/0x33c kernel_init+0x28/0x14c ret_from_fork+0x10/0x20 unreferenced object 0xffff00080170c140 (size 8): comm "swapper/0", pid 1, jiffies 4294667327 hex dump (first 8 bytes): 72 65 73 65 74 00 00 00 reset... backtrace (crc fc24536): kmemleak_alloc+0xf4/0x12c __kmalloc_node_track_caller_noprof+0x3c4/0x584 kstrdup+0x4c/0xcc gpio_shared_make_ref+0x8c/0x16c gpio_shared_of_traverse+0x4e8/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_of_traverse+0x200/0x5f4 gpio_shared_init+0x34/0x1c4 do_one_initcall+0x50/0x280 kernel_init_freeable+0x290/0x33c kernel_init+0x28/0x14c ret_from_fork+0x10/0x20 Fix this by decrementing the reference count of each list entry rather than only the first. Fix verified on the same laptop. Fixes: a060b8c511abb gpiolib: implement low-level, shared GPIO support Signed-off-by: Daniel J Blueman Link: https://patch.msgid.link/20260220093452.101655-1-daniel@quora.org Signed-off-by: Bartosz Golaszewski

Convert more 'alloc_obj' cases to default GFP_KERNEL arguments

2026-02-22T04:03:00+00:00

This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds

Convert 'alloc_flex' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This is the exact same thing as the 'alloc_obj()' version, only much smaller because there are a lot fewer users of the *alloc_flex() interface. As with alloc_obj() version, this was done entirely with mindless brute force, using the same script, except using 'flex' in the pattern rather than 'objs*'. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook