kernel/linux.git/include/linux/parport.h, branch v7.1-rc6

parport: Fix race between port and client registration

2026-05-22T10:19:02+00:00

The parport subsystem registers port devices before they are fully initialised, resulting in a race condition where client drivers such as lp can attach to ports that are not completely initialised or even being torn down. When the port and client drivers are built as modules and loaded around the same time during boot, this occasionally results in a crash. I was able to make this happen reliably in a VM with a PC-style parallel port by patching parport_pc to fail probing: > --- a/drivers/parport/parport_pc.c > +++ b/drivers/parport/parport_pc.c > @@ -2069,7 +2069,7 @@ static struct parport *__parport_pc_probe_port(unsigned long int base, > if (!p) > goto out3; > > - base_res = request_region(base, 3, p->name); > + base_res = NULL; > if (!base_res) > goto out4; > and then running: while true; do modprobe lp & modprobe parport_pc wait rmmod lp parport_pc done for a few seconds. In the long term I think port registration should be changed to put the call to device_add() inside parport_announce_port(), but since the latter currently cannot fail this will require changing all port drivers. For now, add a flag to indicate whether a port has been "announced" and only try to attach client drivers to ports when the flag is set. Fixes: 6fa45a226897 ("parport: add device-model to parport subsystem") Closes: https://bugs.debian.org/1130365 Closes: https://lore.kernel.org/all/6ba903ad-9897-42bb-8c2d-337385cc3746@molgen.mpg.de/ Cc: stable Signed-off-by: Ben Hutchings Acked-by: Sudip Mukherjee Link: https://patch.msgid.link/afo6uBv68GDevbMD@decadent.org.uk Signed-off-by: Greg Kroah-Hartman

parport: Remove parport_driver.devmodel

2024-07-03T14:44:22+00:00

'devmodel' hasn't actually been used since: 'commit 3275158fa52a ("parport: remove use of devmodel")' and everyone now has it set to true and has been fixed up; remove the flag. (There are still comments all over about it) Signed-off-by: Dr. David Alan Gilbert Acked-by: Sudip Mukherjee Link: https://lore.kernel.org/r/20240502154823.67235-4-linux@treblig.org Signed-off-by: Greg Kroah-Hartman

parport: Remove attach function pointer

2024-07-03T14:44:22+00:00

The attach function pointers haven't actually been called since: 'commit 3275158fa52a ("parport: remove use of devmodel")' topped adding entries to the drivers list. If you're converting a driver, look at the 'match_port' function pointer instead. (There are lots of comment references to 'attach' all over, but they probably need some deeper understanding to check the semantics to see if they can be replaced by match_port). Signed-off-by: Dr. David Alan Gilbert Acked-by: Sudip Mukherjee Link: https://lore.kernel.org/r/20240502154823.67235-3-linux@treblig.org Signed-off-by: Greg Kroah-Hartman

parport: Remove 'drivers' list

2024-07-03T14:44:22+00:00

The list has been empty since: 'commit 3275158fa52a ("parport: remove use of devmodel")' This also means we can remove the 'list_head' from struct parport_driver. Signed-off-by: Dr. David Alan Gilbert Acked-by: Sudip Mukherjee Link: https://lore.kernel.org/r/20240502154823.67235-2-linux@treblig.org Signed-off-by: Greg Kroah-Hartman

parport: Use kasprintf() instead of fixed buffer formatting

2023-10-18T08:02:52+00:00

Improve readability and maintainability by replacing a hardcoded string allocation and formatting by the use of the kasprintf() helper. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20231016133135.1203643-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

Merge tag 'char-misc-6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2023-07-03T19:46:47+00:00

Pull Char/Misc updates from Greg KH: "Here is the big set of char/misc and other driver subsystem updates for 6.5-rc1. Lots of different, tiny, stuff in here, from a range of smaller driver subsystems, including pulls from some substems directly: - IIO driver updates and additions - W1 driver updates and fixes (and a new maintainer!) - FPGA driver updates and fixes - Counter driver updates - Extcon driver updates - Interconnect driver updates - Coresight driver updates - mfd tree tag merge needed for other updates on top of that, lots of small driver updates as patches, including: - static const updates for class structures - nvmem driver updates - pcmcia driver fix - lots of other small driver updates and fixes All of these have been in linux-next for a while with no reported problems" * tag 'char-misc-6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (243 commits) bsr: fix build problem with bsr_class static cleanup comedi: make all 'class' structures const char: xillybus: make xillybus_class a static const structure xilinx_hwicap: make icap_class a static const structure virtio_console: make port class a static const structure ppdev: make ppdev_class a static const structure char: misc: make misc_class a static const structure /dev/mem: make mem_class a static const structure char: lp: make lp_class a static const structure dsp56k: make dsp56k_class a static const structure bsr: make bsr_class a static const structure oradax: make 'cl' a static const structure hwtracing: hisi_ptt: Fix potential sleep in atomic context hwtracing: hisi_ptt: Advertise PERF_PMU_CAP_NO_EXCLUDE for PTT PMU hwtracing: hisi_ptt: Export available filters through sysfs hwtracing: hisi_ptt: Add support for dynamically updating the filter list hwtracing: hisi_ptt: Factor out filter allocation and release operation samples: pfsm: add CC_CAN_LINK dependency misc: fastrpc: check return value of devm_kasprintf() coresight: dummy: Update type of mode parameter in dummy_{sink,source}_enable() ...

parport: PC style parport depends on HAS_IOPORT

2023-05-31T18:17:40+00:00

In a future patch HAS_IOPORT=n will result in inb()/outb() and friends not being declared. As PC style parport uses these functions we need to handle this dependency. Co-developed-by: Arnd Bergmann Signed-off-by: Arnd Bergmann Signed-off-by: Niklas Schnelle Link: https://lore.kernel.org/r/20230522105049.1467313-24-schnelle@linux.ibm.com Signed-off-by: Greg Kroah-Hartman

parport: Move magic number "15" to a define

2023-05-24T04:43:25+00:00

Put the size of a parport name behind a define so we can use it in other files. This is a preparation patch to be able to use this size in parport/procfs.c. Signed-off-by: Joel Granados Reviewed-by: Luis Chamberlain Signed-off-by: Luis Chamberlain

parport: remove ax88796 driver

2023-01-16T08:26:06+00:00

The s3c24xx bast platform was removed, so this driver has no users any more and can be removed as well. Acked-by: Sudip Mukherjee Signed-off-by: Arnd Bergmann

parport: Introduce module_parport_driver() helper macro

2021-03-10T12:46:04+00:00

Introduce module_parport_driver() helper macro to reduce boilerplate in the existing and new code. Signed-off-by: Andy Shevchenko Acked-by: Sudip Mukherjee Reviewed-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20210303091642.23929-2-andriy.shevchenko@linux.intel.com Signed-off-by: Mark Brown