It turns out that the vfs_iocb_iter_{read,write}() functions are
entirely broken, and don't actually use the passed-in file pointer for
IO - only for the preparatory work (permission checking and for the
write_iter function lookup).
That worked fine for overlayfs, which always builds the new iocb with
the same file pointer that it passes in, but in the general case it ends
up doing nonsensical things (and could cause an iterator call that
doesn't even match the passed-in file pointer).
This subtly broke the tty conversion to write_iter in commit
9bb48c82ac ("tty: implement write_iter"), because the console
redirection didn't actually end up redirecting anything, since the
passed-in file pointer was basically ignored, and the actual write was
done with the original non-redirected console tty after all.
The main visible effect of this is that the console messages were no
longer logged to /var/log/boot.log during graphical boot.
Fix the issue by simply not using the vfs write "helper" function at
all, and just redirecting the write entirely internally to the tty
layer. Do the target writability permission checks when actually
registering the target tty with TIOCCONS instead of at write time.
Fixes: 9bb48c82ac ("tty: implement write_iter")
Reported-and-tested-by: Hans de Goede <hdegoede@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
layer to use write_iter. Fix the redirected_tty_write declaration
also in n_tty and change the comparisons to use write_iter instead of
write.
[ Also moved the declaration of redirected_tty_write() to the proper
location in a header file. The reason for the bug was the bogus extern
declaration in n_tty.c silently not matching the changed definition in
tty_io.c, and because it wasn't in a shared header file, there was no
cross-checking of the declaration.
Sami noticed because Clang's Control Flow Integrity checking ended up
incidentally noticing the inconsistent declaration. - Linus ]
Fixes: 9bb48c82ac ("tty: implement write_iter")
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull tty/serial fixes from Greg KH:
"Here are three small tty/serial fixes for 5.11-rc5 to resolve reported
problems:
- two patches to fix up writing to ttys with splice
- mvebu-uart driver fix for reported problem
All of these have been in linux-next with no reported problems"
* tag 'tty-5.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
tty: fix up hung_up_tty_write() conversion
tty: implement write_iter
serial: mvebu-uart: fix tx lost characters at power off
We want the single "splice/sendfile to a tty" regression fix into
tty-linus so it can get into 5.11-final, while the larger patch series
fixing "splice/sendfile from a tty" should wait for 5.12-rc1 so that we
get more testing.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This makes the tty layer use the .write_iter() function instead of the
traditional .write() functionality.
That allows writev(), but more importantly also makes it possible to
enable .splice_write() for ttys, reinstating the "splice to tty"
functionality that was lost in commit 36e2c7421f ("fs: don't allow
splice read/write without explicit ops").
Fixes: 36e2c7421f ("fs: don't allow splice read/write without explicit ops")
Reported-by: Oliver Giles <ohw.giles@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull RISC-V fixes from Palmer Dabbelt:
"There are a few more fixes than a normal rc4, largely due to the
bubble introduced by the holiday break:
- return -ENOSYS for syscall number -1, which previously returned an
uninitialized value.
- ensure of_clk_init() has been called in time_init(), without which
clock drivers may not be initialized.
- fix sifive,uart0 driver to properly display the baud rate. A fix to
initialize MPIE that allows interrupts to be processed during
system calls.
- avoid erronously begin tracing IRQs when interrupts are disabled,
which at least triggers suprious lockdep failures.
- workaround for a warning related to calling smp_processor_id()
while preemptible. The warning itself is suprious on currently
availiable systems.
- properly include the generic time VDSO calls. A fix to our kasan
address mapping. A fix to the HiFive Unleashed device tree, which
allows the Ethernet PHY to be properly initialized by Linux (as
opposed to relying on the bootloader).
- defconfig update to include SiFive's GPIO driver, which is present
on the HiFive Unleashed and necessary to initialize the PHY.
- avoid allocating memory while initializing reserved memory.
- avoid allocating the last 4K of memory, as pointers there alias
with syscall errors.
There are also two cleanups that should have no functional effect but
do fix build warnings:
- drop a duplicated definition of PAGE_KERNEL_EXEC.
- properly declare the asm register SP shim.
- cleanup the rv32 memory size Kconfig entry, to reflect the actual
size of memory availiable"
* tag 'riscv-for-linus-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
RISC-V: Fix maximum allowed phsyical memory for RV32
RISC-V: Set current memblock limit
RISC-V: Do not allocate memblock while iterating reserved memblocks
riscv: stacktrace: Move register keyword to beginning of declaration
riscv: defconfig: enable gpio support for HiFive Unleashed
dts: phy: add GPIO number and active state used for phy reset
dts: phy: fix missing mdio device and probe failure of vsc8541-01 device
riscv: Fix KASAN memory mapping.
riscv: Fixup CONFIG_GENERIC_TIME_VSYSCALL
riscv: cacheinfo: Fix using smp_processor_id() in preemptible
riscv: Trace irq on only interrupt is enabled
riscv: Drop a duplicated PAGE_KERNEL_EXEC
riscv: Enable interrupts during syscalls with M-Mode
riscv: Fix sifive serial driver
riscv: Fix kernel time_init()
riscv: return -ENOSYS for syscall -1
This reverts commit 757055ae8d.
The commit caused that ttynull was used as the default console
on several systems[1][2][3]. As a result, the console was
blank even when a better alternative existed.
It happened when there was no console configured
on the command line and ttynull_init() was the first initcall
calling register_console().
Or it happened when /dev/ did not exist when console_on_rootfs()
was called. It was not able to open /dev/console even though
a console driver was registered. It tried to add ttynull console
but it obviously did not help. But ttynull became the preferred
console and was used by /dev/console when it was available later.
The commit tried to fix a historical problem that have been there
for ages. The primary motivation was the commit 3cffa06aee
("printk/console: Allow to disable console output by using console=""
or console=null"). It provided a clean solution for a workaround
that was widely used and worked only by chance.
This revert causes that the console="" or console=null command line
options will again work only by chance. These options will cause that
a particular console will be preferred and the default (tty) ones
will not get enabled. There will be no console registered at
all. As a result there won't be stdin, stdout, and stderr for
the init process. But it worked exactly this way even before.
The proper solution has to fulfill many conditions:
+ Register ttynull only when explicitly required or as
the ultimate fallback.
+ ttynull should get associated with /dev/console but it must
not become preferred console when used as a fallback.
Especially, it must still be possible to replace it
by a better console later.
Such a change requires clean up of the register_console() code.
Otherwise, it would be even harder to follow. Especially, the use
of has_preferred_console and CON_CONSDEV flag is tricky. The clean
up is risky. The ordering of consoles is not well defined. And
any changes tend to break existing user settings.
Do the revert at the least risky solution for now.
[1] https://lore.kernel.org/linux-kselftest/20201221144302.GR4077@smile.fi.intel.com/
[2] https://lore.kernel.org/lkml/d2a3b3c0-e548-7dd1-730f-59bc5c04e191@synopsys.com/
[3] https://patchwork.ozlabs.org/project/linux-um/patch/20210105120128.10854-1-thomas@m3y3r.de/
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: Vineet Gupta <vgupta@synopsys.com>
Reported-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Setup the port uartclk in sifive_serial_probe() so that the base baud
rate is correctly printed during device probe instead of always showing
"0". I.e. the probe message is changed from
38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1,
base_baud = 0) is a SiFive UART v0
to the correct:
38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1,
base_baud = 115200) is a SiFive UART v0
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Commit c685af1108 ("serial: mvebu-uart: fix tx lost characters") fixed tx
lost characters at low baud rates but started causing tx lost characters
when kernel is going to power off or reboot.
TX_EMP tells us when transmit queue is empty therefore all characters were
transmitted. TX_RDY tells us when CPU can send a new character.
Therefore we need to use different check prior transmitting new character
and different check after all characters were sent.
This patch splits polling code into two functions: wait_for_xmitr() which
waits for TX_RDY and wait_for_xmite() which waits for TX_EMP.
When rebooting A3720 platform without this patch on UART is print only:
[ 42.699�
And with this patch on UART is full output:
[ 39.530216] reboot: Restarting system
Fixes: c685af1108 ("serial: mvebu-uart: fix tx lost characters")
Signed-off-by: Pali Rohár <pali@kernel.org>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201223191931.18343-1-pali@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull OpenRISC updates from Stafford Horne:
- New drivers and OpenRISC support for the LiteX platform
- A bug fix to support userspace gdb debugging
- Fixes one compile issue with blk-iocost
* tag 'for-linus' of git://github.com/openrisc/linux:
openrisc: add local64.h to fix blk-iocost build
openrisc: fix trap for debugger breakpoint signalling
openrisc: add support for LiteX
drivers/tty/serial: add LiteUART driver
dt-bindings: serial: document LiteUART bindings
drivers/soc/litex: add LiteX SoC Controller driver
dt-bindings: soc: document LiteX SoC Controller bindings
dt-bindings: vendor: add vendor prefix for LiteX
Pull printk updates from Petr Mladek:
- Finally allow parallel writes and reads into/from the lockless
ringbuffer. But it is not a complete solution. Readers are still
serialized against each other. And nested writes are still prevented
by printk_safe per-CPU buffers.
- Use ttynull as the ultimate fallback for /dev/console.
- Officially allow disabling console output by using console="" or
console=null
- A few code cleanups
* tag 'printk-for-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk: remove logbuf_lock writer-protection of ringbuffer
printk: inline log_output(),log_store() in vprintk_store()
printk: remove obsolete dead assignment
printk/console: Allow to disable console output by using console="" or console=null
init/console: Use ttynull as a fallback when there is no console
printk: ringbuffer: Reference text_data_ring directly in callees.
Pull tty / serial updates from Greg KH:
"Here is the "large" set of tty and serial patches for 5.11-rc1.
Nothing major at all, some cleanups and some driver removals, always a
nice sign:
- build warning cleanups
- vt locking and logic unwinding and cleanups
- tiny serial driver fixes and updates
- removal of the synclink serial driver as it's no longer needed
- removal of dead termiox code
All of this has been in linux-next for a while with no reported issues"
* tag 'tty-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (89 commits)
serial: 8250_pci: Drop bogus __refdata annotation
tty: serial: meson: enable console as module
serial: 8250_omap: Avoid FIFO corruption caused by MDR1 access
serial: imx: Move imx_uart_probe_dt() content into probe()
serial: imx: Remove unneeded of_device_get_match_data() NULL check
tty: Fix whitespace inconsistencies in vt_io_ioctl
serial_core: Check for port state when tty is in error state
dt-bindings: serial: Update DT binding docs to support SiFive FU740 SoC
tty: use const parameters in port-flag accessors
tty: use assign_bit() in port-flag accessors
earlycon: drop semicolon from earlycon macro
tty: Remove dead termiox code
tty/serial/imx: Enable TXEN bit in imx_poll_init().
tty : serial: jsm: Fixed file by adding spacing
tty: serial: uartlite: Support probe deferral
earlycon: simplify earlycon-table implementation
tty: serial: bcm63xx: lower driver dependencies
serial: mxs-auart: Remove unneeded platform_device_id
serial: 8250-mtk: Fix reference leak in mtk8250_probe
serial: imx: Remove unused .id_table support
...
It has been observed that once per 300-1300 port openings the first
transmitted byte is being corrupted on AM3352 ("v" written to FIFO appeared
as "e" on the wire). It only happened if single byte has been transmitted
right after port open, which means, DMA is not used for this transfer and
the corruption never happened afterwards.
Therefore I've carefully re-read the MDR1 errata (link below), which says
"when accessing the MDR1 registers that causes a dummy under-run condition
that will freeze the UART in IrDA transmission. In UART mode, this may
corrupt the transferred data". Strictly speaking,
omap_8250_mdr1_errataset() performs a read access and if the value is the
same as should be written, exits without errata-recommended FIFO reset.
A brief check of the serial_omap_mdr1_errataset() from the competing
omap-serial driver showed it has no read access of MDR1. After removing the
read access from omap_8250_mdr1_errataset() the data corruption never
happened any more.
Link: https://www.ti.com/lit/er/sprz360i/sprz360i.pdf
Fixes: 61929cf016 ("tty: serial: Add 8250-core based omap driver")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Link: https://lore.kernel.org/r/20201210055257.1053028-1-alexander.sverdlin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since 5.10-rc1 i.MX is a devicetree-only platform and the NULL check on
of_device_get_match_data() is no longer needed.
This check was only needed when this driver supported both DT and non-DT
platforms.
Remove the unneeded of_device_get_match_data() NULL check.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20201126124643.3371-1-festevam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
At the moment opening a serial device node (such as /dev/ttyS3)
succeeds even if there is no actual serial device behind it.
Reading/writing/ioctls fail as expected because the uart port is not
initialized (the type is PORT_UNKNOWN) and the TTY_IO_ERROR error state
bit is set fot the tty.
However setting line discipline does not have these checks
8250_port.c (8250 is the default choice made by univ8250_console_init()).
As the result of PORT_UNKNOWN, uart_port::iobase is NULL which
a platform translates onto some address accessing which produces a crash
like below.
This adds tty_port_initialized() to uart_set_ldisc() to prevent the crash.
Found by syzkaller.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Link: https://lore.kernel.org/r/20201203055834.45838-1-aik@ozlabs.ru
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, locking of ->session is very inconsistent; most places
protect it using the legacy tty mutex, but disassociate_ctty(),
__do_SAK(), tiocspgrp() and tiocgsid() don't.
Two of the writers hold the ctrl_lock (because they already need it for
->pgrp), but __proc_set_tty() doesn't do that yet.
On a PREEMPT=y system, an unprivileged user can theoretically abuse
this broken locking to read 4 bytes of freed memory via TIOCGSID if
tiocgsid() is preempted long enough at the right point. (Other things
might also go wrong, especially if root-only ioctls are involved; I'm
not sure about that.)
Change the locking on ->session such that:
- tty_lock() is held by all writers: By making disassociate_ctty()
hold it. This should be fine because the same lock can already be
taken through the call to tty_vhangup_session().
The tricky part is that we need to shorten the area covered by
siglock to be able to take tty_lock() without ugly retry logic; as
far as I can tell, this should be fine, since nothing in the
signal_struct is touched in the `if (tty)` branch.
- ctrl_lock is held by all writers: By changing __proc_set_tty() to
hold the lock a little longer.
- All readers that aren't holding tty_lock() hold ctrl_lock: By
adding locking to tiocgsid() and __do_SAK(), and expanding the area
covered by ctrl_lock in tiocspgrp().
Cc: stable@kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tiocspgrp() takes two tty_struct pointers: One to the tty that userspace
passed to ioctl() (`tty`) and one to the TTY being changed (`real_tty`).
These pointers are different when ioctl() is called with a master fd.
To properly lock real_tty->pgrp, we must take real_tty->ctrl_lock.
This bug makes it possible for racing ioctl(TIOCSPGRP, ...) calls on
both sides of a PTY pair to corrupt the refcount of `struct pid`,
leading to use-after-free errors.
Fixes: 47f86834bb ("redo locking of tty->pgrp")
CC: stable@kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linus Torvalds
Sami Tolvanen
Greg Kroah-Hartman
Petr Mladek
Damien Le Moal
Pali Rohár
Geert Uytterhoeven
Kevin Hilman
Alexander Sverdlin
Fabio Estevam
Yan.Gao
Alexey Kardashevskiy
Jann Horn