Changes in 4.4.248: (39 commits)
net/af_iucv: set correct sk_protocol for child sockets
rose: Fix Null pointer dereference in rose_send_frame()
usbnet: ipheth: fix connectivity with iOS 14
bonding: wait for sysfs kobject destruction before freeing struct slave
netfilter: bridge: reset skb->pkt_type after NF_INET_POST_ROUTING traversal
net/x25: prevent a couple of overflows
cxgb3: fix error return code in t3_sge_alloc_qset()
net: pasemi: fix error return code in pasemi_mac_open()
dt-bindings: net: correct interrupt flags in examples
Input: xpad - support Ardwiino Controllers
Input: i8042 - add ByteSpeed touchpad to noloop table
powerpc: Stop exporting __clear_user which is now inlined.
btrfs: sysfs: init devices outside of the chunk_mutex
vlan: consolidate VLAN parsing code and limit max parsing depth
usb: gadget: f_fs: Use local copy of descriptors for userspace copy
USB: serial: kl5kusb105: fix memleak on open
USB: serial: ch341: add new Product ID for CH341A
USB: serial: ch341: sort device-id entries
USB: serial: option: add Fibocom NL668 variants
USB: serial: option: add support for Thales Cinterion EXS82
tty: Fix ->pgrp locking in tiocspgrp()
ALSA: hda/realtek - Add new codec supported for ALC897
ALSA: hda/generic: Add option to enforce preferred_dacs pairs
tty: Fix ->session locking
cifs: fix potential use-after-free in cifs_echo_request()
i2c: imx: Fix reset of I2SR_IAL flag
i2c: imx: Check for I2SR_IAL after every byte
arm64: assembler: make adr_l work in modules under KASLR
iommu/amd: Set DTE[IntTabLen] to represent 512 IRTEs
spi: Introduce device-managed SPI controller allocation
spi: bcm2835: Fix use-after-free on unbind
spi: bcm2835: Release the DMA channel if probe fails after dma_init
tracing: Fix userstacktrace option for instances
btrfs: cleanup cow block on error
mm/userfaultfd: do not access vma->vm_mm after calling handle_userfault()
gfs2: check for empty rgrp tree in gfs2_ri_update
Input: i8042 - fix error return code in i8042_setup_aux()
x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes
Linux 4.4.248
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Conflicts:
arch/arm64/kernel/head.S
commit c8bcd9c5be24fb9e6132e97da5a35e55a83e36b9 upstream.
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>
Changes in 4.4.224: (87 commits)
USB: serial: qcserial: Add DW5816e support
Revert "net: phy: Avoid polling PHY with PHY_IGNORE_INTERRUPTS"
dp83640: reverse arguments to list_add_tail
net/mlx4_core: Fix use of ENOSPC around mlx4_counter_alloc()
sch_sfq: validate silly quantum values
sch_choke: avoid potential panic in choke_reset()
Revert "ACPI / video: Add force_native quirk for HP Pavilion dv6"
enic: do not overwrite error code
ipv6: fix cleanup ordering for ip6_mr failure
binfmt_elf: move brk out of mmap when doing direct loader exec
x86/apm: Don't access __preempt_count with zeroed fs
Revert "IB/ipoib: Update broadcast object if PKey value was changed in index 0"
USB: uas: add quirk for LaCie 2Big Quadra
USB: serial: garmin_gps: add sanity checking for data length
batman-adv: fix batadv_nc_random_weight_tq
scripts/decodecode: fix trapping instruction formatting
phy: micrel: Ensure interrupts are reenabled on resume
binfmt_elf: Do not move brk for INTERP-less ET_EXEC
ext4: add cond_resched() to ext4_protect_reserved_inode
net: ipv6: add net argument to ip6_dst_lookup_flow
net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup
blktrace: Fix potential deadlock between delete & sysfs ops
blktrace: fix unlocked access to init/start-stop/teardown
blktrace: fix trace mutex deadlock
blktrace: Protect q->blk_trace with RCU
blktrace: fix dereference after null check
ptp: do not explicitly set drvdata in ptp_clock_register()
ptp: use is_visible method to hide unused attributes
ptp: create "pins" together with the rest of attributes
chardev: add helper function to register char devs with a struct device
ptp: Fix pass zero to ERR_PTR() in ptp_clock_register
ptp: fix the race between the release of ptp_clock and cdev
ptp: free ptp device pin descriptors properly
net: handle no dst on skb in icmp6_send
net/sonic: Fix a resource leak in an error handling path in 'jazz_sonic_probe()'
net: moxa: Fix a potential double 'free_irq()'
drop_monitor: work around gcc-10 stringop-overflow warning
scsi: sg: add sg_remove_request in sg_write
spi: spi-dw: Add lock protect dw_spi rx/tx to prevent concurrent calls
cifs: Check for timeout on Negotiate stage
cifs: Fix a race condition with cifs_echo_request
dmaengine: pch_dma.c: Avoid data race between probe and irq handler
dmaengine: mmp_tdma: Reset channel error on release
drm/qxl: lost qxl_bo_kunmap_atomic_page in qxl_image_init_helper()
ipc/util.c: sysvipc_find_ipc() incorrectly updates position index
net: openvswitch: fix csum updates for MPLS actions
gre: do not keep the GRE header around in collect medata mode
mm/memory_hotplug.c: fix overflow in test_pages_in_a_zone()
scsi: qla2xxx: Avoid double completion of abort command
i40e: avoid NVM acquire deadlock during NVM update
net/mlx5: Fix driver load error flow when firmware is stuck
netfilter: conntrack: avoid gcc-10 zero-length-bounds warning
IB/mlx4: Test return value of calls to ib_get_cached_pkey
pnp: Use list_for_each_entry() instead of open coding
gcc-10 warnings: fix low-hanging fruit
kbuild: compute false-positive -Wmaybe-uninitialized cases in Kconfig
Stop the ad-hoc games with -Wno-maybe-initialized
gcc-10: disable 'zero-length-bounds' warning for now
gcc-10: disable 'array-bounds' warning for now
gcc-10: disable 'stringop-overflow' warning for now
gcc-10: disable 'restrict' warning for now
block: defer timeouts to a workqueue
blk-mq: Allow timeouts to run while queue is freezing
blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter
blk-mq: Allow blocking queue tag iter callbacks
x86/paravirt: Remove the unused irq_enable_sysexit pv op
gcc-10: avoid shadowing standard library 'free()' in crypto
net: fix a potential recursive NETDEV_FEAT_CHANGE
net: ipv4: really enforce backoff for redirects
netlabel: cope with NULL catmap
ALSA: hda/realtek - Limit int mic boost for Thinkpad T530
ALSA: rawmidi: Fix racy buffer resize under concurrent accesses
ALSA: rawmidi: Initialize allocated buffers
USB: gadget: fix illegal array access in binding with UDC
ARM: dts: imx27-phytec-phycard-s-rdk: Fix the I2C1 pinctrl entries
x86: Fix early boot crash on gcc-10, third try
exec: Move would_dump into flush_old_exec
usb: gadget: net2272: Fix a memory leak in an error handling path in 'net2272_plat_probe()'
usb: gadget: audio: Fix a missing error return value in audio_bind()
usb: gadget: legacy: fix error return code in gncm_bind()
usb: gadget: legacy: fix error return code in cdc_bind()
Revert "ALSA: hda/realtek: Fix pop noise on ALC225"
ARM: dts: r8a7740: Add missing extal2 to CPG node
KVM: x86: Fix off-by-one error in kvm_vcpu_ioctl_x86_setup_mce
Makefile: disallow data races on gcc-10 as well
scsi: iscsi: Fix a potential deadlock in the timeout handler
Linux 4.4.224
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Conflicts:
kernel/trace/blktrace.c
sound/core/rawmidi.c
commit 9d82973e032e246ff5663c9805fbb5407ae932e3 upstream.
Due to a bug-report that was compiler-dependent, I updated one of my
machines to gcc-10. That shows a lot of new warnings. Happily they
seem to be mostly the valid kind, but it's going to cause a round of
churn for getting rid of them..
This is the really low-hanging fruit of removing a couple of zero-sized
arrays in some core code. We have had a round of these patches before,
and we'll have many more coming, and there is nothing special about
these except that they were particularly trivial, and triggered more
warnings than most.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Changes in 4.4.131: (44 commits)
ext4: prevent right-shifting extents beyond EXT_MAX_BLOCKS
ext4: set h_journal if there is a failure starting a reserved handle
ext4: add validity checks for bitmap block numbers
ext4: fix bitmap position validation
usbip: usbip_host: fix to hold parent lock for device_attach() calls
usbip: vhci_hcd: Fix usb device and sockfd leaks
USB: serial: simple: add libtransistor console
USB: serial: ftdi_sio: use jtag quirk for Arrow USB Blaster
USB: serial: cp210x: add ID for NI USB serial console
usb: core: Add quirk for HP v222w 16GB Mini
USB: Increment wakeup count on remote wakeup.
ALSA: usb-audio: Skip broken EU on Dell dock USB-audio
virtio: add ability to iterate over vqs
virtio_console: free buffers after reset
drm/virtio: fix vq wait_event condition
tty: Don't call panic() at tty_ldisc_init()
tty: n_gsm: Fix long delays with control frame timeouts in ADM mode
tty: n_gsm: Fix DLCI handling for ADM mode if debug & 2 is not set
tty: Use __GFP_NOFAIL for tty_ldisc_get()
ALSA: opl3: Hardening for potential Spectre v1
ALSA: asihpi: Hardening for potential Spectre v1
ALSA: hdspm: Hardening for potential Spectre v1
ALSA: rme9652: Hardening for potential Spectre v1
ALSA: control: Hardening for potential Spectre v1
ALSA: core: Report audio_tstamp in snd_pcm_sync_ptr
ALSA: seq: oss: Fix unbalanced use lock for synth MIDI device
ALSA: seq: oss: Hardening for potential Spectre v1
ALSA: hda: Hardening for potential Spectre v1
ALSA: hda/realtek - Add some fixes for ALC233
mtd: cfi: cmdset_0001: Do not allow read/write to suspend erase block.
mtd: cfi: cmdset_0001: Workaround Micron Erase suspend bug.
mtd: cfi: cmdset_0002: Do not allow read/write to suspend erase block.
kobject: don't use WARN for registration failures
scsi: sd: Defer spinning up drive while SANITIZE is in progress
ARM: amba: Make driver_override output consistent with other buses
ARM: amba: Fix race condition with driver_override
ARM: amba: Don't read past the end of sysfs "driver_override" buffer
ASoC: fsl_esai: Fix divisor calculation failure at lower ratio
libceph: validate con->state at the top of try_write()
x86/ipc: Fix x32 version of shmid64_ds and msqid64_ds
x86/smpboot: Don't use mwait_play_dead() on AMD systems
serial: mctrl_gpio: export mctrl_gpio_disable_ms and mctrl_gpio_init
serial: mctrl_gpio: Add missing module license
Linux 4.4.131
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Changes in 4.4.129: (98 commits)
media: v4l2-compat-ioctl32: don't oops on overlay
parisc: Fix out of array access in match_pci_device()
perf intel-pt: Fix overlap detection to identify consecutive buffers correctly
perf intel-pt: Fix sync_switch
perf intel-pt: Fix error recovery from missing TIP packet
perf intel-pt: Fix timestamp following overflow
radeon: hide pointless #warning when compile testing
Revert "perf tests: Decompress kernel module before objdump"
block/loop: fix deadlock after loop_set_status
s390/qdio: don't retry EQBS after CCQ 96
s390/qdio: don't merge ERROR output buffers
s390/ipl: ensure loadparm valid flag is set
getname_kernel() needs to make sure that ->name != ->iname in long case
rtl8187: Fix NULL pointer dereference in priv->conf_mutex
hwmon: (ina2xx) Fix access to uninitialized mutex
cdc_ether: flag the Cinterion AHS8 modem by gemalto as WWAN
slip: Check if rstate is initialized before uncompressing
lan78xx: Correctly indicate invalid OTP
x86/hweight: Get rid of the special calling convention
x86/hweight: Don't clobber %rdi
tty: make n_tty_read() always abort if hangup is in progress
ubifs: Check ubifs_wbuf_sync() return code
ubi: fastmap: Don't flush fastmap work on detach
ubi: Fix error for write access
ubi: Reject MLC NAND
fs/reiserfs/journal.c: add missing resierfs_warning() arg
resource: fix integer overflow at reallocation
ipc/shm: fix use-after-free of shm file via remap_file_pages()
mm, slab: reschedule cache_reap() on the same CPU
usb: musb: gadget: misplaced out of bounds check
ARM: dts: at91: at91sam9g25: fix mux-mask pinctrl property
ARM: dts: at91: sama5d4: fix pinctrl compatible string
xen-netfront: Fix hang on device removal
regmap: Fix reversed bounds check in regmap_raw_write()
ACPI / video: Add quirk to force acpi-video backlight on Samsung 670Z5E
ACPI / hotplug / PCI: Check presence of slot itself in get_slot_status()
USB:fix USB3 devices behind USB3 hubs not resuming at hibernate thaw
usb: dwc3: pci: Properly cleanup resource
HID: i2c-hid: fix size check and type usage
powerpc/powernv: Handle unknown OPAL errors in opal_nvram_write()
powerpc/64: Fix smp_wmb barrier definition use use lwsync consistently
powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops
powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops
HID: Fix hid_report_len usage
HID: core: Fix size as type u32
ASoC: ssm2602: Replace reg_default_raw with reg_default
thunderbolt: Resume control channel after hibernation image is created
random: use a tighter cap in credit_entropy_bits_safe()
jbd2: if the journal is aborted then don't allow update of the log tail
ext4: don't update checksum of new initialized bitmaps
ext4: fail ext4_iget for root directory if unallocated
RDMA/ucma: Don't allow setting RDMA_OPTION_IB_PATH without an RDMA device
ALSA: pcm: Fix UAF at PCM release via PCM timer access
IB/srp: Fix srp_abort()
IB/srp: Fix completion vector assignment algorithm
dmaengine: at_xdmac: fix rare residue corruption
um: Use POSIX ucontext_t instead of struct ucontext
iommu/vt-d: Fix a potential memory leak
mmc: jz4740: Fix race condition in IRQ mask update
clk: mvebu: armada-38x: add support for 1866MHz variants
clk: mvebu: armada-38x: add support for missing clocks
clk: bcm2835: De-assert/assert PLL reset signal when appropriate
thermal: imx: Fix race condition in imx_thermal_probe()
watchdog: f71808e_wdt: Fix WD_EN register read
ALSA: oss: consolidate kmalloc/memset 0 call to kzalloc
ALSA: pcm: Use ERESTARTSYS instead of EINTR in OSS emulation
ALSA: pcm: Avoid potential races between OSS ioctls and read/write
ALSA: pcm: Return -EBUSY for OSS ioctls changing busy streams
ALSA: pcm: Fix mutex unbalance in OSS emulation ioctls
ALSA: pcm: Fix endless loop for XRUN recovery in OSS emulation
vfio-pci: Virtualize PCIe & AF FLR
vfio/pci: Virtualize Maximum Payload Size
vfio/pci: Virtualize Maximum Read Request Size
ext4: don't allow r/w mounts if metadata blocks overlap the superblock
drm/radeon: Fix PCIe lane width calculation
ext4: fix crashes in dioread_nolock mode
ext4: fix deadlock between inline_data and ext4_expand_extra_isize_ea()
ALSA: line6: Use correct endpoint type for midi output
ALSA: rawmidi: Fix missing input substream checks in compat ioctls
ALSA: hda - New VIA controller suppor no-snoop path
HID: hidraw: Fix crash on HIDIOCGFEATURE with a destroyed device
MIPS: uaccess: Add micromips clobbers to bzero invocation
MIPS: memset.S: EVA & fault support for small_memset
MIPS: memset.S: Fix return of __clear_user from Lpartial_fixup
MIPS: memset.S: Fix clobber of v1 in last_fixup
powerpc/eeh: Fix enabling bridge MMIO windows
powerpc/lib: Fix off-by-one in alternate feature patching
jffs2_kill_sb(): deal with failed allocations
hypfs_kill_super(): deal with failed allocations
rpc_pipefs: fix double-dput()
Don't leak MNT_INTERNAL away from internal mounts
autofs: mount point create should honour passed in mode
mm: allow GFP_{FS,IO} for page_cache_read page cache allocation
mm/filemap.c: fix NULL pointer in page_cache_tree_insert()
ext4: bugfix for mmaped pages in mpage_release_unused_pages()
fanotify: fix logic of events on child
writeback: safer lock nesting
Linux 4.4.129
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Conflicts:
arch/x86/lib/Makefile
commit 28b0f8a6962a24ed21737578f3b1b07424635c9e upstream.
A tty is hung up by __tty_hangup() setting file->f_op to
hung_up_tty_fops, which is skipped on ttys whose write operation isn't
tty_write(). This means that, for example, /dev/console whose write
op is redirected_tty_write() is never actually marked hung up.
Because n_tty_read() uses the hung up status to decide whether to
abort the waiting readers, the lack of hung-up marking can lead to the
following scenario.
1. A session contains two processes. The leader and its child. The
child ignores SIGHUP.
2. The leader exits and starts disassociating from the controlling
terminal (/dev/console).
3. __tty_hangup() skips setting f_op to hung_up_tty_fops.
4. SIGHUP is delivered and ignored.
5. tty_ldisc_hangup() is invoked. It wakes up the waits which should
clear the read lockers of tty->ldisc_sem.
6. The reader wakes up but because tty_hung_up_p() is false, it
doesn't abort and goes back to sleep while read-holding
tty->ldisc_sem.
7. The leader progresses to tty_ldisc_lock() in tty_ldisc_hangup()
and is now stuck in D sleep indefinitely waiting for
tty->ldisc_sem.
The following is Alan's explanation on why some ttys aren't hung up.
http://lkml.kernel.org/r/20171101170908.6ad08580@alans-desktop
1. It broke the serial consoles because they would hang up and close
down the hardware. With tty_port that *should* be fixable properly
for any cases remaining.
2. The console layer was (and still is) completely broken and doens't
refcount properly. So if you turn on console hangups it breaks (as
indeed does freeing consoles and half a dozen other things).
As neither can be fixed quickly, this patch works around the problem
by introducing a new flag, TTY_HUPPING, which is used solely to tell
n_tty_read() that hang-up is in progress for the console and the
readers should be aborted regardless of the hung-up status of the
device.
The following is a sample hung task warning caused by this issue.
INFO: task agetty:2662 blocked for more than 120 seconds.
Not tainted 4.11.3-dbg-tty-lockup-02478-gfd6c7ee-dirty #28
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
0 2662 1 0x00000086
Call Trace:
__schedule+0x267/0x890
schedule+0x36/0x80
schedule_timeout+0x23c/0x2e0
ldsem_down_write+0xce/0x1f6
tty_ldisc_lock+0x16/0x30
tty_ldisc_hangup+0xb3/0x1b0
__tty_hangup+0x300/0x410
disassociate_ctty+0x6c/0x290
do_exit+0x7ef/0xb00
do_group_exit+0x3f/0xa0
get_signal+0x1b3/0x5d0
do_signal+0x28/0x660
exit_to_usermode_loop+0x46/0x86
do_syscall_64+0x9c/0xb0
entry_SYSCALL64_slow_path+0x25/0x25
The following is the repro. Run "$PROG /dev/console". The parent
process hangs in D state.
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <time.h>
#include <termios.h>
int main(int argc, char **argv)
{
struct sigaction sact = { .sa_handler = SIG_IGN };
struct timespec ts1s = { .tv_sec = 1 };
pid_t pid;
int fd;
if (argc < 2) {
fprintf(stderr, "test-hung-tty /dev/$TTY\n");
return 1;
}
/* fork a child to ensure that it isn't already the session leader */
pid = fork();
if (pid < 0) {
perror("fork");
return 1;
}
if (pid > 0) {
/* top parent, wait for everyone */
while (waitpid(-1, NULL, 0) >= 0)
;
if (errno != ECHILD)
perror("waitpid");
return 0;
}
/* new session, start a new session and set the controlling tty */
if (setsid() < 0) {
perror("setsid");
return 1;
}
fd = open(argv[1], O_RDWR);
if (fd < 0) {
perror("open");
return 1;
}
if (ioctl(fd, TIOCSCTTY, 1) < 0) {
perror("ioctl");
return 1;
}
/* fork a child, sleep a bit and exit */
pid = fork();
if (pid < 0) {
perror("fork");
return 1;
}
if (pid > 0) {
nanosleep(&ts1s, NULL);
printf("Session leader exiting\n");
exit(0);
}
/*
* The child ignores SIGHUP and keeps reading from the controlling
* tty. Because SIGHUP is ignored, the child doesn't get killed on
* parent exit and the bug in n_tty makes the read(2) block the
* parent's control terminal hangup attempt. The parent ends up in
* D sleep until the child is explicitly killed.
*/
sigaction(SIGHUP, &sact, NULL);
printf("Child reading tty\n");
while (1) {
char buf[1024];
if (read(fd, buf, sizeof(buf)) < 0) {
perror("read");
return 1;
}
}
return 0;
}
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@llwyncelyn.cymru>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Changes in 4.4.127: (73 commits)
mtd: jedec_probe: Fix crash in jedec_read_mfr()
ALSA: pcm: Use dma_bytes as size parameter in dma_mmap_coherent()
ALSA: pcm: potential uninitialized return values
perf/hwbp: Simplify the perf-hwbp code, fix documentation
partitions/msdos: Unable to mount UFS 44bsd partitions
usb: gadget: define free_ep_req as universal function
usb: gadget: change len to size_t on alloc_ep_req()
usb: gadget: fix usb_ep_align_maybe endianness and new usb_ep_align
usb: gadget: align buffer size when allocating for OUT endpoint
usb: gadget: f_hid: fix: Prevent accessing released memory
kprobes/x86: Fix to set RWX bits correctly before releasing trampoline
ACPI, PCI, irq: remove redundant check for null string pointer
writeback: fix the wrong congested state variable definition
PCI: Make PCI_ROM_ADDRESS_MASK a 32-bit constant
dm ioctl: remove double parentheses
Input: mousedev - fix implicit conversion warning
netfilter: nf_nat_h323: fix logical-not-parentheses warning
genirq: Use cpumask_available() for check of cpumask variable
cpumask: Add helper cpumask_available()
selinux: Remove unnecessary check of array base in selinux_set_mapping()
fs: compat: Remove warning from COMPATIBLE_IOCTL
jiffies.h: declare jiffies and jiffies_64 with ____cacheline_aligned_in_smp
frv: declare jiffies to be located in the .data section
audit: add tty field to LOGIN event
tty: provide tty_name() even without CONFIG_TTY
netfilter: ctnetlink: Make some parameters integer to avoid enum mismatch
selinux: Remove redundant check for unknown labeling behavior
arm64: avoid overflow in VA_START and PAGE_OFFSET
xfrm_user: uncoditionally validate esn replay attribute struct
RDMA/ucma: Check AF family prior resolving address
RDMA/ucma: Fix use-after-free access in ucma_close
RDMA/ucma: Ensure that CM_ID exists prior to access it
RDMA/ucma: Check that device is connected prior to access it
RDMA/ucma: Check that device exists prior to accessing it
RDMA/ucma: Don't allow join attempts for unsupported AF family
RDMA/ucma: Introduce safer rdma_addr_size() variants
net: xfrm: use preempt-safe this_cpu_read() in ipcomp_alloc_tfms()
xfrm: Refuse to insert 32 bit userspace socket policies on 64 bit systems
netfilter: bridge: ebt_among: add more missing match size checks
netfilter: x_tables: add and use xt_check_proc_name
Bluetooth: Fix missing encryption refresh on Security Request
llist: clang: introduce member_address_is_nonnull()
scsi: virtio_scsi: always read VPD pages for multiqueue too
usb: dwc2: Improve gadget state disconnection handling
USB: serial: ftdi_sio: add RT Systems VX-8 cable
USB: serial: ftdi_sio: add support for Harman FirmwareHubEmulator
USB: serial: cp210x: add ELDAT Easywave RX09 id
mei: remove dev_err message on an unsupported ioctl
media: usbtv: prevent double free in error case
parport_pc: Add support for WCH CH382L PCI-E single parallel port card.
crypto: ahash - Fix early termination in hash walk
crypto: x86/cast5-avx - fix ECB encryption when long sg follows short one
fs/proc: Stop trying to report thread stacks
staging: comedi: ni_mio_common: ack ai fifo error interrupts.
Input: i8042 - add Lenovo ThinkPad L460 to i8042 reset list
Input: i8042 - enable MUX on Sony VAIO VGN-CS series to fix touchpad
vt: change SGR 21 to follow the standards
Documentation: pinctrl: palmas: Add ti,palmas-powerhold-override property definition
ARM: dts: dra7: Add power hold and power controller properties to palmas
ARM: dts: am57xx-beagle-x15-common: Add overide powerhold property
md/raid10: reset the 'first' at the end of loop
net: hns: Fix ethtool private flags
nospec: Move array_index_nospec() parameter checking into separate macro
nospec: Kill array_index_nospec_mask_check()
Revert "PCI/MSI: Stop disabling MSI/MSI-X in pci_device_shutdown()"
Revert "ARM: dts: am335x-pepper: Fix the audio CODEC's reset pin"
Revert "ARM: dts: omap3-n900: Fix the audio CODEC's reset pin"
Revert "cpufreq: Fix governor module removal race"
Revert "mtip32xx: use runtime tag to initialize command header"
spi: davinci: fix up dma_mapping_error() incorrect patch
net: cavium: liquidio: fix up "Avoid dma_unmap_single on uninitialized ndata"
Revert "ip6_vti: adjust vti mtu according to mtu of lower device"
Linux 4.4.127
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Conflicts:
arch/arm64/include/asm/memory.h
fs/proc/task_mmu.c
include/linux/jiffies.h
net/ipv4/netfilter/nf_nat_h323.c
commit 188e3c5cd2b672620291e64a21f1598fe91e40b6 upstream.
The audit subsystem just started printing the name of the tty,
but that causes a build failure when CONFIG_TTY is disabled:
kernel/built-in.o: In function `audit_log_task_info':
memremap.c:(.text+0x5e34c): undefined reference to `tty_name'
kernel/built-in.o: In function `audit_set_loginuid':
memremap.c:(.text+0x63b34): undefined reference to `tty_name'
This adds tty_name() to the list of functions that are provided
as trivial stubs in that configuration.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: db0a6fb5d97a ("audit: add tty field to LOGIN event")
Signed-off-by: Paul Moore <paul@paul-moore.com>
[natechancellor: tty_paranoia_check still exists]
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This function allows the port's scheduling policy to be changed. Some
tty ports (like Bluetooth ones), need a higher priority to reduce
jitter.
Bug: 36106419
Test: Bluetooth audio
Change-Id: If11e21c55924314910d602573c735c6afae09709
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This makes each tty_port have their own kthread, hopefully allowing them
a bit more freedom in scheduling when they reveive data.
Based on a patch from Philip Cuadra <philipcuadra@google.com>
Based on a patch from Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Bug: 36106419
Test: run Bluetooth audio, ensure separate tty thread is created.
Signed-off-by: Philip Cuadra <philipcuadra@google.com>
Change-Id: I9fd25235b26a66acb37a40304c356209b74ad46c
commit 0f40fbbcc34e093255a2b2d70b6b0fb48c3f39aa upstream.
OpenSSH expects the (non-blocking) read() of pty master to return
EAGAIN only if it has received all of the slave-side output after
it has received SIGCHLD. This used to work on pre-3.12 kernels.
This fix effectively forces non-blocking read() and poll() to
block for parallel i/o to complete for all ttys. It also unwinds
these changes:
1) f8747d4a46
tty: Fix pty master read() after slave closes
2) 52bce7f8d4
pty, n_tty: Simplify input processing on final close
3) 1a48632ffe
pty: Fix input race when closing
Inspired by analysis and patch from Marc Aurele La France <tsi@tuyoix.net>
Reported-by: Volth <openssh@volth.com>
Reported-by: Marc Aurele La France <tsi@tuyoix.net>
BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=52
BugLink: https://bugzilla.mindrot.org/show_bug.cgi?id=2492
Signed-off-by: Brian Bloniarz <brian.bloniarz@gmail.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f33798deecbd59a2955f40ac0ae2bc7dff54c069 upstream.
commit 9ce119f318 ("tty: Fix GPF in flush_to_ldisc()") fixed a
GPF caused by a line discipline which does not define a receive_buf()
method.
However, the vt driver (and speakup driver also) pushes selection
data directly to the line discipline receive_buf() method via
tty_ldisc_receive_buf(). Fix the same problem in tty_ldisc_receive_buf().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0bfd464d3fdd5bb322f9cace4cc47f1796545cf7 upstream.
Allow a signal to interrupt the wait for a tty reopen; eg., if
the tty has starting final close and is waiting for the device to
drain.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce API functions to restart and cancel tty buffer work, rather
than manipulate buffer work directly.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The job_control() check in n_tty_read() has nearly identical purpose
and results as tty_check_change(). Both functions' purpose is to
determine if the current task's pgrp is the foreground pgrp for the tty,
and if not, to signal the current pgrp.
Introduce __tty_check_change() which takes the signal to send
and performs the shared operations for job control() and
tty_check_change().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With the removal of tty_wait_until_sent_from_close(), tty drivers
no longer wait during open for parallel closes to complete (instead,
the tty core waits before calling the driver open() method). Thus,
the close_wait waitqueue is no longer used for waiting.
Remove struct tty_port::close_wait.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_wait_until_sent_from_close() drops the tty lock while waiting
for the tty driver to finish sending previously accepted data (ie.,
data remaining in its write buffer and transmit fifo).
tty_wait_until_sent_from_close() was added by commit a57a7bf3fc
("TTY: define tty_wait_until_sent_from_close") to prevent the entire
tty subsystem from being unable to open new ttys while waiting for
one tty to close while output drained.
However, since commit 0911261d4c ("tty: Don't take tty_mutex for tty
count changes"), holding a tty lock while closing does not prevent other
ttys from being opened/closed/hung up, but only prevents lifetime event
changes for the tty under lock.
Holding the tty lock while waiting for output to drain does prevent
parallel non-blocking opens (O_NONBLOCK) from advancing or returning
while the tty lock is held. However, all parallel opens _already_
block even if the tty lock is dropped while closing and the parallel
open advances. Blocking in open has been in mainline since at least 2.6.29
(see tty_port_block_til_ready(); note the test for O_NONBLOCK is _after_
the wait while ASYNC_CLOSING).
IOW, before this patch a non-blocking open will sleep anyway for the
_entire_ duration of a parallel hardware shutdown, and when it wakes, the
error return will cause a release of its tty, and it will restart with
a fresh attempt to open. Similarly with a blocking open that is already
waiting; when it's woken, the hardware shutdown has already completed
to ASYNC_INITIALIZED is not set, which forces a release and restart as
well.
So, holding the tty lock across the _entire_ close (which is what this
patch does), even while waiting for output to drain, is equivalent to
the current outcome wrt parallel opens.
Cc: Alan Cox <alan@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Karsten Keil <isdn@linux-pingi.de>
CC: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce tty_debug() macro to output uniform debug information for
tty core debug messages (function name and tty name).
Note: printk(KERN_DEBUG) is retained here over pr_debug() since
messages can be enabled in non-DEBUG builds.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A read() from a pty master may mistakenly indicate EOF (errno == -EIO)
after the pty slave has closed, even though input data remains to be read.
For example,
pty slave | input worker | pty master
| |
| | n_tty_read()
pty_write() | | input avail? no
add data | | sleep
schedule worker --->| | .
|---> flush_to_ldisc() | .
pty_close() | fill read buffer | .
wait for worker | wakeup reader --->| .
| read buffer full? |---> input avail ? yes
|<--- yes - exit worker | copy 4096 bytes to user
TTY_OTHER_CLOSED <---| |<--- kick worker
| |
**** New read() before worker starts ****
| | n_tty_read()
| | input avail? no
| | TTY_OTHER_CLOSED? yes
| | return -EIO
Several conditions are required to trigger this race:
1. the ldisc read buffer must become full so the input worker exits
2. the read() count parameter must be >= 4096 so the ldisc read buffer
is empty
3. the subsequent read() occurs before the kicked worker has processed
more input
However, the underlying cause of the race is that data is pipelined, while
tty state is not; ie., data already written by the pty slave end is not
yet visible to the pty master end, but state changes by the pty slave end
are visible to the pty master end immediately.
Pipeline the TTY_OTHER_CLOSED state through input worker to the reader.
1. Introduce TTY_OTHER_DONE which is set by the input worker when
TTY_OTHER_CLOSED is set and either the input buffers are flushed or
input processing has completed. Readers/polls are woken when
TTY_OTHER_DONE is set.
2. Reader/poll checks TTY_OTHER_DONE instead of TTY_OTHER_CLOSED.
3. A new input worker is started from pty_close() after setting
TTY_OTHER_CLOSED, which ensures the TTY_OTHER_DONE state will be
set if the last input worker is already finished (or just about to
exit).
Remove tty_flush_to_ldisc(); no in-tree callers.
Fixes: 52bce7f8d4 ("pty, n_tty: Simplify input processing on final close")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=96311
BugLink: http://bugs.launchpad.net/bugs/1429756
Cc: <stable@vger.kernel.org> # 3.19+
Reported-by: Andy Whitcroft <apw@canonical.com>
Reported-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_name no longer uses the buf parameter, so remove it along with all
the 64 byte stack buffers that used to be passed in.
Mostly generated by the coccinelle script
@depends on patch@
identifier buf;
constant C;
expression tty;
@@
- char buf[C];
<+...
- tty_name(tty, buf)
+ tty_name(tty)
...+>
allmodconfig compiles, so I'm fairly confident the stack buffers
weren't used for other purposes as well.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All users of tty_name pass the result directly to a printf-like
function. This means we can actually let tty_name return the literal
"NULL tty" or tty->name directly, avoiding the strcpy and a lot of
medium-sized stack buffers. In preparation for that, make the return
type const char*.
While at it, we can also constify the tty parameter.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_set_termios() is an internal helper intended for file scope use.
UART drivers which are capable of driving the RTS pin must
properly handle the tiocmset() method, regardless of termios settings.
A failure to do so is a UART driver bug and should be fixed there.
Do not use this interface to workaround UART driver bugs.
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: <linux-bluetooth@vger.kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
BRKINT and ISIG requires input and output flush when a signal char
is received. However, the order of operations is significant since
parallel i/o may be ongoing.
Merge the signal handling for BRKINT with ISIG handling.
Process the signal first. This ensures any ongoing i/o is aborted;
without this, a waiting writer may continue writing after the flush
occurs and after the signal char has been echoed.
Write lock the termios_rwsem, which excludes parallel writers from
pushing new i/o until after the output buffers are flushed; claiming
the write lock is necessary anyway to exclude parallel readers while
the read buffer is flushed.
Subclass the termios_rwsem for ptys since the slave pty performing
the flush may appear to reorder the termios_rwsem->tty buffer lock
lock order; adding annotation clarifies that
slave tty_buffer lock-> slave termios_rwsem -> master tty_buffer lock
is a valid lock order.
Flush the echo buffer. In this context, the echo buffer is 'output'.
Otherwise, the output will appear discontinuous because the output buffer
was cleared which contains older output than the echo buffer.
Open-code the read buffer flush since the input worker does not need
kicking (this is the input worker).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The pty driver does not clear its write buffer when commanded.
This is to avoid an apparent deadlock between parallel flushes from
both pty ends; specifically when handling either BRK or INTR input.
However, parallel flushes from this source is not possible since
the pty master can never be set to BRKINT or ISIG. Parallel flushes
from other sources are possible but these do not threaten deadlocks.
Annotate the tty buffer mutex for lockdep to represent the nested
tty_buffer locking which occurs when the pty slave is processing input
(its buffer mutex held) and receives INTR or BRK and acquires the
linked tty buffer mutex via tty_buffer_flush().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Besides nested legacy_mutex locking which is required on pty pair
teardown, other nested pty operations require lock subclassing.
Move lock subclass definition to tty interface header, include/linux/tty.h,
and document its use.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty->closing is a bitfield member; prevent corruption from non-atomic
update by assigning a unique memory location.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial_console_init() is not defined by the tty core; remove
declaration.
Note that the powerpc arch boot code contains a serial_console_init()
declaration in arch/powerpc/boot/ops.h which is restricted to
the powerpc arch boot.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_ldisc_flush() first clears the line discipline input buffer,
then clears the tty flip buffers. However, this allows for existing
data in the tty flip buffers to be added after the ldisc input
buffer has been cleared, but before the flip buffers have been cleared.
Add an optional ldisc parameter to tty_buffer_flush() to allow
tty_ldisc_flush() to pass the ldisc to clear.
NB: Initially, the plan was to do this automatically in
tty_buffer_flush(). However, an audit of the behavior of existing
line disciplines showed that performing a ldisc buffer flush on
ioctl(TCFLSH) was not always the outcome. For example, some line
disciplines have flush_buffer() methods but not ioctl() methods,
so a ->flush_buffer() command would be unexpected.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Eliminate the requirement of specifying the tty lock nesting at
lock time; instead, set the lock subclass for slave ptys at pty
install (normal ttys and master ptys use subclass 0).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When releasing the master pty, the slave pty also needs to be locked
to prevent concurrent tty count changes for the slave pty and to
ensure that only one parallel master and slave release observe the
final close, and proceed to destruct the pty pair. Conversely, when
releasing the slave pty, locking the master pty is not necessary
(since the master's state can be inferred by the slave tty count).
Introduce tty_lock_slave()/tty_unlock_slave() which acquires/releases
the tty lock of the slave pty. Remove tty_lock_pair()/tty_unlock_pair().
Dropping the tty_lock is no longer required to re-establish a stable
lock order.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that re-open is not permitted for a legacy BSD pty master,
using TTY_CLOSING to indicate when a tty can be torn-down is
no longer necessary.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that tty_ldisc_hangup() does not drop the tty lock, it is no
longer possible to observe TTY_HUPPING while holding the tty lock
on another cpu.
Remove TTY_HUPPING bit definition.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_pair_get_pty() has no in-tree users and tty_pair_get_tty()
has only one file-local user. Remove the external declarations,
the export declarations, and declare tty_pair_get_tty() static.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit c545b66c69,
'tty: Serialize tcflow() with other tty flow control changes' and
commit 99416322dd,
'tty: Workaround Alpha non-atomic byte storage in tty_struct' work around
compiler bugs and non-atomic storage on multiple arches by padding
bitfields out to the declared type which is unsigned long. However, the
width varies by arch.
Pad bitfields to actual width of unsigned long (which is BITS_PER_LONG).
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Alpha EV4/EV5 cpus can corrupt adjacent byte and short data because
those cpus use RMW to store byte and short data. Thus, concurrent adjacent
byte stores could become corrupted, if serialized by a different lock.
tty_struct uses different locks to protect certain fields within the
structure, and thus is vulnerable to byte stores which are not atomic.
Merge the ->ctrl_status byte and packet mode bit, both protected by the
->ctrl_lock, into an unsigned long.
The padding bits are necessary to force the compiler to allocate the
type specified; otherwise, gcc will ignore the type specifier and
allocate the minimum number of bytes required to store the bitfield.
In turn, this would allow Alpha EV4/EV5 cpus to corrupt adjacent byte
or short storage (because those cpus use RMW to store byte and short data).
gcc versions < 4.7.2 will also corrupt storage adjacent to bitfields
smaller than unsigned long on ia64, ppc64, hppa64, and sparc64, thus
requiring more than unsigned int storage (which would otherwise be
sufficient to fix the Alpha non-atomic storage problem).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Relocate the file-scope function, send_prio_char(), as a global
helper tty_send_xchar(). Remove the global declarations for
tty_write_lock()/tty_write_unlock(), as these are file-scope only now.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use newly-introduced tty->flow_lock to serialize updates to
tty->flow_stopped (via tcflow()) and with concurrent tty flow
control changes from other sources.
Merge the storage for ->stopped and ->flow_stopped, now that both
flags are serialized by ->flow_lock.
The padding bits are necessary to force the compiler to allocate the
type specified; otherwise, gcc will ignore the type specifier and
allocate the minimum number of bytes necessary to store the bitfield.
In turn, this would allow Alpha EV4 and EV5 cpus to corrupt adjacent
byte storage because those cpus use RMW to store byte and short data.
gcc versions < 4.7.2 will also corrupt storage adjacent to bitfields
smaller than unsigned long on ia64, ppc64, hppa64 and sparc64, thus
requiring more than unsigned int storage (which would otherwise be
sufficient to workaround the Alpha non-atomic byte/short storage problem).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Without serialization, the flow control state can become inverted
wrt. the actual hardware state. For example,
CPU 0 | CPU 1
stop_tty() |
lock ctrl_lock |
tty->stopped = 1 |
unlock ctrl_lock |
| start_tty()
| lock ctrl_lock
| tty->stopped = 0
| unlock ctrl_lock
| driver->start()
driver->stop() |
In this case, the flow control state now indicates the tty has
been started, but the actual hardware state has actually been stopped.
Introduce tty->flow_lock spinlock to serialize tty flow control changes.
Split out unlocked __start_tty()/__stop_tty() flavors for use by
ioctl(TCXONC) in follow-on patch.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The stopped, hw_stopped, flow_stopped and packet bits are smp-unsafe
and interrupt-unsafe. For example,
CPU 0 | CPU 1
|
tty->flow_stopped = 1 | tty->hw_stopped = 0
One of these updates will be corrupted, as the bitwise operation
on the bitfield is non-atomic.
Ensure each flag has a separate memory location, so concurrent
updates do not corrupt orthogonal states. Because DEC Alpha EV4 and EV5
cpus (from 1995) perform RMW on smaller-than-machine-word storage,
"separate memory location" must be int instead of byte.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The two functions alloc_tty_struct and initialize_tty_struct are
always called together. Merge them into alloc_tty_struct, updating its
prototype and the only two callers of these functions.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 6a20dbd6ca.
Although the commit correctly identifies an unsafe race condition
between __tty_buffer_request_room() and flush_to_ldisc(), the commit
fixes the race with an unnecessary spinlock in a lockless algorithm.
The follow-on commit, "tty: Fix lockless tty buffer race" fixes
the race locklessly.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
