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Rafael Mendonca ee180e867c uio: uio_dmem_genirq: Fix missing unlock in irq configuration [ Upstream commit `9de255c461` ] Commit `b74351287d` ("uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol()") started calling disable_irq() without holding the spinlock because it can sleep. However, that fix introduced another bug: if interrupt is already disabled and a new disable request comes in, then the spinlock is not unlocked: root@localhost:~# printf '\x00\x00\x00\x00' > /dev/uio0 root@localhost:~# printf '\x00\x00\x00\x00' > /dev/uio0 root@localhost:~# [ 14.851538] BUG: scheduling while atomic: bash/223/0x00000002 [ 14.851991] Modules linked in: uio_dmem_genirq uio myfpga(OE) bochs drm_vram_helper drm_ttm_helper ttm drm_kms_helper drm snd_pcm ppdev joydev psmouse snd_timer snd e1000fb_sys_fops syscopyarea parport sysfillrect soundcore sysimgblt input_leds pcspkr i2c_piix4 serio_raw floppy evbug qemu_fw_cfg mac_hid pata_acpi ip_tables x_tables autofs4 [last unloaded: parport_pc] [ 14.854206] CPU: 0 PID: 223 Comm: bash Tainted: G OE 6.0.0-rc7 #21 [ 14.854786] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 [ 14.855664] Call Trace: [ 14.855861] <TASK> [ 14.856025] dump_stack_lvl+0x4d/0x67 [ 14.856325] dump_stack+0x14/0x1a [ 14.856583] __schedule_bug.cold+0x4b/0x5c [ 14.856915] __schedule+0xe81/0x13d0 [ 14.857199] ? idr_find+0x13/0x20 [ 14.857456] ? get_work_pool+0x2d/0x50 [ 14.857756] ? __flush_work+0x233/0x280 [ 14.858068] ? __schedule+0xa95/0x13d0 [ 14.858307] ? idr_find+0x13/0x20 [ 14.858519] ? get_work_pool+0x2d/0x50 [ 14.858798] schedule+0x6c/0x100 [ 14.859009] schedule_hrtimeout_range_clock+0xff/0x110 [ 14.859335] ? tty_write_room+0x1f/0x30 [ 14.859598] ? n_tty_poll+0x1ec/0x220 [ 14.859830] ? tty_ldisc_deref+0x1a/0x20 [ 14.860090] schedule_hrtimeout_range+0x17/0x20 [ 14.860373] do_select+0x596/0x840 [ 14.860627] ? __kernel_text_address+0x16/0x50 [ 14.860954] ? poll_freewait+0xb0/0xb0 [ 14.861235] ? poll_freewait+0xb0/0xb0 [ 14.861517] ? rpm_resume+0x49d/0x780 [ 14.861798] ? common_interrupt+0x59/0xa0 [ 14.862127] ? asm_common_interrupt+0x2b/0x40 [ 14.862511] ? __uart_start.isra.0+0x61/0x70 [ 14.862902] ? __check_object_size+0x61/0x280 [ 14.863255] core_sys_select+0x1c6/0x400 [ 14.863575] ? vfs_write+0x1c9/0x3d0 [ 14.863853] ? vfs_write+0x1c9/0x3d0 [ 14.864121] ? _copy_from_user+0x45/0x70 [ 14.864526] do_pselect.constprop.0+0xb3/0xf0 [ 14.864893] ? do_syscall_64+0x6d/0x90 [ 14.865228] ? do_syscall_64+0x6d/0x90 [ 14.865556] __x64_sys_pselect6+0x76/0xa0 [ 14.865906] do_syscall_64+0x60/0x90 [ 14.866214] ? syscall_exit_to_user_mode+0x2a/0x50 [ 14.866640] ? do_syscall_64+0x6d/0x90 [ 14.866972] ? do_syscall_64+0x6d/0x90 [ 14.867286] ? do_syscall_64+0x6d/0x90 [ 14.867626] entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] stripped [ 14.872959] </TASK> ('myfpga' is a simple 'uio_dmem_genirq' driver I wrote to test this) The implementation of "uio_dmem_genirq" was based on "uio_pdrv_genirq" and it is used in a similar manner to the "uio_pdrv_genirq" driver with respect to interrupt configuration and handling. At the time "uio_dmem_genirq" was introduced, both had the same implementation of the 'uio_info' handlers irqcontrol() and handler(). Then commit `34cb275283` ("UIO: Fix concurrency issue"), which was only applied to "uio_pdrv_genirq", ended up making them a little different. That commit, among other things, changed disable_irq() to disable_irq_nosync() in the implementation of irqcontrol(). The motivation there was to avoid a deadlock between irqcontrol() and handler(), since it added a spinlock in the irq handler, and disable_irq() waits for the completion of the irq handler. By changing disable_irq() to disable_irq_nosync() in irqcontrol(), we also avoid the sleeping-while-atomic bug that commit `b74351287d` ("uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol()") was trying to fix. Thus, this fixes the missing unlock in irqcontrol() by importing the implementation of irqcontrol() handler from the "uio_pdrv_genirq" driver. In the end, it reverts commit `b74351287d` ("uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol()") and change disable_irq() to disable_irq_nosync(). It is worth noting that this still does not address the concurrency issue fixed by commit `34cb275283` ("UIO: Fix concurrency issue"). It will be addressed separately in the next commits. Split out from commit `34cb275283` ("UIO: Fix concurrency issue"). Fixes: `b74351287d` ("uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol()") Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com> Link: https://lore.kernel.org/r/20220930224100.816175-2-rafaelmendsr@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		History 2022-12-31 13:32:38 +01:00
arch	riscv: Fix P4D_SHIFT definition for 3-level page table mode	2022-12-31 13:32:38 +01:00
block	block: clear ->slave_dir when dropping the main slave_dir reference	2022-12-31 13:32:12 +01:00
certs	certs: make system keyring depend on built-in x509 parser	2022-09-24 04:31:18 +09:00
crypto	crypto: tcrypt - Fix multibuffer skcipher speed test mem leak	2022-12-31 13:32:34 +01:00
Documentation	dt-bindings: visconti-pcie: Fix interrupts array max constraints	2022-12-31 13:32:33 +01:00
drivers	uio: uio_dmem_genirq: Fix missing unlock in irq configuration	2022-12-31 13:32:38 +01:00
fs	f2fs: fix iostat parameter for discard	2022-12-31 13:32:38 +01:00
include	RDMA/hns: Fix incorrect sge nums calculation	2022-12-31 13:32:33 +01:00
init	init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash	2022-11-22 22:42:38 +09:00
io_uring	io_uring: Fix a null-ptr-deref in io_tctx_exit_cb()	2022-12-07 06:45:20 -07:00
ipc	ipc: fix memory leak in init_mqueue_fs()	2022-12-31 13:32:01 +01:00
kernel	padata: Fix list iterator in padata_do_serial()	2022-12-31 13:32:34 +01:00
lib	lib/notifier-error-inject: fix error when writing -errno to debugfs file	2022-12-31 13:31:58 +01:00
LICENSES	LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers	2021-12-16 14:33:10 +01:00
mm	9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address	2022-12-10 17:10:52 -08:00
net	net: dsa: tag_8021q: avoid leaking ctx on dsa_tag_8021q_register() error path	2022-12-31 13:32:29 +01:00
rust	Kbuild: add Rust support	2022-09-28 09:02:20 +02:00
samples	samples/bpf: Fix MAC address swapping in xdp2_kern	2022-12-31 13:32:03 +01:00
scripts	- Handle different output of readelf on different distros running	2022-11-27 12:08:17 -08:00
security	apparmor: Fix memleak in alloc_ns()	2022-12-31 13:32:31 +01:00
sound	ALSA: mts64: fix possible null-ptr-defer in snd_mts64_interrupt	2022-12-31 13:32:22 +01:00
tools	bpftool: Fix memory leak in do_build_table_cb	2022-12-31 13:32:23 +01:00
usr	usr/gen_init_cpio.c: remove unnecessary -1 values from int file	2022-10-03 14:21:44 -07:00
virt	Merge branch 'kvm-dwmw2-fixes' into HEAD	2022-11-23 18:59:45 -05:00
.clang-format	inet: ping: use hlist_nulls rcu iterator during lookup	2022-12-01 12:42:46 +01:00
.cocciconfig	scripts: add Linux .cocciconfig for coccinelle	2016-07-22 12:13:39 +02:00
.get_maintainer.ignore	get_maintainer: add Alan to .get_maintainer.ignore	2022-08-20 15:17:44 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	Kbuild: add Rust support	2022-09-28 09:02:20 +02:00
.mailmap	9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address	2022-12-10 17:10:52 -08:00
.rustfmt.toml	rust: add `.rustfmt.toml`	2022-09-28 09:02:20 +02:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Remove Michal Marek from Kbuild maintainers	2022-11-16 14:53:00 +09:00
Kbuild	Kbuild updates for v6.1	2022-10-10 12:00:45 -07:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address	2022-12-10 17:10:52 -08:00
Makefile	Linux 6.1.1	2022-12-21 17:48:12 +01:00
README	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.