CVE-2022-50652uio: uio_dmem_genirq: Fix missing unlock in irq configuration

In the Linux kernel, the following vulnerability has been resolved: uio: uio_dmem_genirq: Fix missing unlock in irq configuration Commit b74351287d4b ("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 34cb27528398 ("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-whil ---truncated---

CVSS

Not yet scored

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Linux

NVD analysis

Deferred

Record last updated

May 23, 2026

First seen by InfoSec Signals

Oct 9, 2026

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