#
# Font configuration
#
config FONT_SUPPORT
tristate
if FONT_SUPPORT
config FONTS
bool "Select compiled-in fonts"
depends on FRAMEBUFFER_CONSOLE || STI_CONSOLE
help
Say Y here if you would like to use fonts other than the default
your frame buffer console usually use.
Note that the answer to this question won't directly affect the
kernel: saying N will just cause the configurator to skip all
the questions about foreign fonts.
If unsure, say N (the default choices are safe).
config FONT_8x8
bool "VGA 8x8 font" if FONTS
depends on FRAMEBUFFER_CONSOLE || STI_CONSOLE
default y if !SPARC && !FONTS
help
This is the "high resolution" font for the VGA frame buffer (the one
provided by the text console 80x50 (and higher) modes).
Note that this is a poor quality font. The VGA 8x16 font is quite a
lot more readable.
Given the resolution provided by the frame buffer device, answer N
here is safe.
config FONT_8x16
bool "VGA 8x16 font" if FONTS
default y if !SPARC && !FONTS
help
This is the "high resolution" font for the VGA frame buffer (the one
provided by the VGA text console 80x25 mode.
If unsure, say Y.
config FONT_6x11
bool "Mac console 6x11 font (not supported by all drivers)" if FONTS
depends on FRAMEBUFFER_CONSOLE || STI_CONSOLE
default y if !SPARC && !FONTS && MAC
help
Small console font with Macintosh-style high-half glyphs. Some Mac
framebuffer drivers don't support this one at all.
config FONT_7x14
bool "console 7x14 font (not supported by all drivers)" if FONTS
depends on FRAMEBUFFER_CONSOLE
help
Console font with characters just a bit smaller than the default.
If the standard 8x16 font is a little too big for you, say Y.
Otherwise, say N.
config FONT_PEARL_8x8
bool "Pearl (old m68k) console 8x8 font" if FONTS
depends on FRAMEBUFFER_CONSOLE
default y if !SPARC && !FONTS && AMIGA
help
Small console font with PC-style control-character and high-half
glyphs.
config FONT_ACORN_8x8
bool "Acorn console 8x8 font" if FONTS
depends on FRAMEBUFFER_CONSOLE
default y if !SPARC && !FONTS && ARM && ARCH_ACORN
help
Small console font with PC-style control characters and high-half
glyphs.
config FONT_MINI_4x6
bool "Mini 4x6 font"
depends on !SPARC && FONTS
config FONT_6x10
bool "Medium-size 6x10 font"
depends on !SPARC && FONTS
help
Medium-size console font. Suitable for framebuffer consoles on
embedded devices with a 320x240 screen, to get a reasonable number
of characters (53x24) that are still at a readable size.
config FONT_SUN8x16
bool "Sparc console 8x16 font"
depends on FRAMEBUFFER_CONSOLE && (!SPARC && FONTS || SPARC)
help
This is the high resolution console font for Sun machines. Say Y.
config FONT_SUN12x22
bool "Sparc console 12x22 font (not supported by all drivers)"
depends on FRAMEBUFFER_CONSOLE && (!SPARC && FONTS || SPARC)
help
This is the high resolution console font for Sun machines with very
big letters (like the letters used in the SPARC PROM). If the
standard font is unreadable for you, say Y, otherwise say N.
config FONT_10x18
bool "console 10x18 font (not supported by all drivers)" if FONTS
depends on FRAMEBUFFER_CONSOLE
help
This is a high resolution console font for machines with very
big letters. It fits between the sun 12x22 and the normal 8x16 font.
If other fonts are too big or too small for you, say Y, otherwise say N.
config FONT_AUTOSELECT
def_bool y
depends on !FONT_8x8
depends on !FONT_6x11
depends on !FONT_7x14
depends on !FONT_PEARL_8x8
depends on !FONT_ACORN_8x8
depends on !FONT_MINI_4x6
depends on !FONT_6x10
depends on !FONT_SUN8x16
depends on !FONT_SUN12x22
depends on !FONT_10x18
select FONT_8x16
endif # FONT_SUPPORT
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return
"true" IFF they acquire a reference. But the return value from
atomic_long_inc_not_zero() is a long and may have high bits set,
e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines
is bool so the reference may actually be acquired but the routines
return "false" which results in a reference leak since the caller
assumes it does not need to do a corresponding percpu_ref_put().
This was seen when performing CPU hotplug during I/O, as hangs in
blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start)
raced with percpu_ref_tryget (blk_mq_timeout_work).
Sample stack trace:
__switch_to+0x2c0/0x450
__schedule+0x2f8/0x970
schedule+0x48/0xc0
blk_mq_freeze_queue_wait+0x94/0x120
blk_mq_queue_reinit_work+0xb8/0x180
blk_mq_queue_reinit_prepare+0x84/0xa0
cpuhp_invoke_callback+0x17c/0x600
cpuhp_up_callbacks+0x58/0x150
_cpu_up+0xf0/0x1c0
do_cpu_up+0x120/0x150
cpu_subsys_online+0x64/0xe0
device_online+0xb4/0x120
online_store+0xb4/0xc0
dev_attr_store+0x68/0xa0
sysfs_kf_write+0x80/0xb0
kernfs_fop_write+0x17c/0x250
__vfs_write+0x6c/0x1e0
vfs_write+0xd0/0x270
SyS_write+0x6c/0x110
system_call+0x38/0xe0
Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS,
and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests.
However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0
and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set.
The fix is to make the tryget routines use an actual boolean internally instead
of the atomic long result truncated to a int.
Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints
Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751
Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com>
Reviewed-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints")
Cc: stable@vger.kernel.org # v3.18+