linux-stable.git/drivers/uio, branch linux-4.9.y

uio: uio_dmem_genirq: Fix deadlock between irq config and handling

2023-01-07T11:07:24+00:00

[ Upstream commit 118b918018175d9fcd8db667f905012e986cc2c9 ]

This fixes a concurrency issue addressed in commit 34cb27528398 ("UIO: Fix
concurrency issue"):

  "In a SMP case there was a race condition issue between
  Uio_pdrv_genirq_irqcontrol() running on one CPU and irq handler on
  another CPU. Fix it by spin_locking shared resources access inside irq
  handler."

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
merged, both had the same implementation of the 'uio_info' handlers
irqcontrol() and handler(), thus, both had the same concurrency issue
mentioned by the above commit. However, the above patch was only applied to
the "uio_pdrv_genirq" driver.

Split out from commit 34cb27528398 ("UIO: Fix concurrency issue").

Fixes: 0a0c3b5a24bd ("Add new uio device for dynamic memory allocation")
Signed-off-by: Rafael Mendonca 
Link: https://lore.kernel.org/r/20220930224100.816175-3-rafaelmendsr@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

uio: uio_dmem_genirq: Fix missing unlock in irq configuration

2023-01-07T11:07:24+00:00

[ Upstream commit 9de255c461d1b3f0242b3ad1450c3323a3e00b34 ]

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]  
[   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]  

('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-while-atomic bug that commit b74351287d4b ("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 b74351287d4b ("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 34cb27528398 ("UIO: Fix concurrency issue"). It will be
addressed separately in the next commits.

Split out from commit 34cb27528398 ("UIO: Fix concurrency issue").

Fixes: b74351287d4b ("uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol()")
Signed-off-by: Rafael Mendonca 
Link: https://lore.kernel.org/r/20220930224100.816175-2-rafaelmendsr@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

uio_pdrv_genirq: fix use without device tree and no interrupt

2020-07-22T07:10:53+00:00

commit bf12fdf0ab728ca8e5933aac46dd972c0dd0421e upstream.

While e3a3c3a20555 ("UIO: fix uio_pdrv_genirq with device tree but no
interrupt") added support for using uio_pdrv_genirq for devices without
interrupt for device tree platforms, the removal of uio_pdrv in
26dac3c49d56 ("uio: Remove uio_pdrv and use uio_pdrv_genirq instead")
broke the support for non device tree platforms.

This change fixes this, so that uio_pdrv_genirq can be used without
interrupt on all platforms.

This still leaves the support that uio_pdrv had for custom interrupt
handler lacking, as uio_pdrv_genirq does not handle it (yet).

Fixes: 26dac3c49d56 ("uio: Remove uio_pdrv and use uio_pdrv_genirq instead")
Signed-off-by: Esben Haabendal 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200701145659.3978-3-esben@geanix.com
Signed-off-by: Greg Kroah-Hartman

uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol()

2020-02-28T14:42:20+00:00

[ Upstream commit b74351287d4bd90636c3f48bc188c2f53824c2d4 ]

The driver may sleep while holding a spinlock.
The function call path (from bottom to top) in Linux 4.19 is:

kernel/irq/manage.c, 523:
	synchronize_irq in disable_irq
drivers/uio/uio_dmem_genirq.c, 140:
	disable_irq in uio_dmem_genirq_irqcontrol
drivers/uio/uio_dmem_genirq.c, 134:
	_raw_spin_lock_irqsave in uio_dmem_genirq_irqcontrol

synchronize_irq() can sleep at runtime.

To fix this bug, disable_irq() is called without holding the spinlock.

This bug is found by a static analysis tool STCheck written by myself.

Signed-off-by: Jia-Ju Bai 
Link: https://lore.kernel.org/r/20191218094405.6009-1-baijiaju1990@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

uio: Fix an Oops on load

2018-11-27T15:09:41+00:00

commit 432798195bbce1f8cd33d1c0284d0538835e25fb upstream.

I was trying to solve a double free but I introduced a more serious
NULL dereference bug.  The problem is that if there is an IRQ which
triggers immediately, then we need "info->uio_dev" but it's not set yet.

This patch puts the original initialization back to how it was and just
sets info->uio_dev to NULL on the error path so it should solve both
the Oops and the double free.

Fixes: f019f07ecf6a ("uio: potential double frees if __uio_register_device() fails")
Reported-by: Mathias Thore 
Signed-off-by: Dan Carpenter 
Cc: stable 
Tested-by: Mathias Thore 
Signed-off-by: Greg Kroah-Hartman

uio: ensure class is registered before devices

2018-11-13T19:16:53+00:00

[ Upstream commit ae61cf5b9913027c6953a79ed3894da4f47061bd ]

When both uio and the uio drivers are built in the kernel, it is possible
for a driver to register devices before the uio class is registered.

This may result in a NULL pointer dereference later on in
get_device_parent() when accessing the class glue_dirs spinlock.

The trace looks like that:

Unable to handle kernel NULL pointer dereference at virtual address 00000140
[...]
[] _raw_spin_lock+0x14/0x48
[] device_add+0x154/0x6a0
[] device_create_groups_vargs+0x120/0x128
[] device_create+0x54/0x60
[] __uio_register_device+0x120/0x4a8
[] jaguar2_pci_probe+0x2d4/0x558
[] local_pci_probe+0x3c/0xb8
[] pci_device_probe+0x11c/0x180
[] driver_probe_device+0x22c/0x2d8
[] __driver_attach+0xbc/0xc0
[] bus_for_each_dev+0x4c/0x98
[] driver_attach+0x20/0x28
[] bus_add_driver+0x1b8/0x228
[] driver_register+0x60/0xf8
[] __pci_register_driver+0x40/0x48

Return EPROBE_DEFER in that case so the driver can register the device
later.

Signed-off-by: Alexandre Belloni 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

uio: potential double frees if __uio_register_device() fails

2018-09-19T20:47:13+00:00

[ Upstream commit f019f07ecf6a6b8bd6d7853bce70925d90af02d1 ]

The uio_unregister_device() function assumes that if "info->uio_dev" is
non-NULL that means "info" is fully allocated.  Setting info->uio_de
has to be the last thing in the function.

In the current code, if request_threaded_irq() fails then we return with
info->uio_dev set to non-NULL but info is not fully allocated and it can
lead to double frees.

Fixes: beafc54c4e2f ("UIO: Add the User IO core code")
Signed-off-by: Dan Carpenter 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

uio: fix incorrect memory leak cleanup

2018-04-13T17:47:59+00:00

[ Upstream commit 0d83539092ddb1ab79b4d65bccb866bf07ea2ccd ]

Commit 75f0aef6220d ("uio: fix memory leak") has fixed up some
memory leaks during the failure paths of the addition of uio
attributes, but still is not correct entirely. A kobject_uevent()
failure still needs a kobject_put() and the kobject container
structure allocation failure before the kobject_init() doesn't
need a kobject_put(). Fix this properly.

Fixes: 75f0aef6220d ("uio: fix memory leak")
Signed-off-by: Suman Anna 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

uio: fix dmem_region_start computation

2016-08-31T11:07:30+00:00

The variable i contains a total number of resources (including
IORESOURCE_IRQ). However, we want the dmem_region_start to point
after the last resource of type IORESOURCE_MEM. The original behaviour
leads (very likely) to skipping several UIO mapping regions and makes
them useless. Fix this by computing dmem_region_start from the uiomem
which points to the last used UIO mapping.

Fixes: 0a0c3b5a24bd ("Add new uio device for dynamic memory allocation")

Signed-off-by: Jan Viktorin 
Signed-off-by: Greg Kroah-Hartman

uio: add missing error codes

2016-05-01T21:11:12+00:00

My static checker complains that "ret" could be uninitialized at the
end, which is true but it's more likely that it would be set to zero.

Signed-off-by: Dan Carpenter 
Signed-off-by: Greg Kroah-Hartman