kernel/git/stable/linux-stable.git/drivers/s390/char, branch linux-3.16.y

s390/smp: fix CPU hotplug deadlock with CPU rescan

2019-05-02T20:41:20+00:00

commit b7cb707c373094ce4008d4a6ac9b6b366ec52da5 upstream. smp_rescan_cpus() is called without the device_hotplug_lock, which can lead to a dedlock when a new CPU is found and immediately set online by a udev rule. This was observed on an older kernel version, where the cpu_hotplug_begin() loop was still present, and it resulted in hanging chcpu and systemd-udev processes. This specific deadlock will not show on current kernels. However, there may be other possible deadlocks, and since smp_rescan_cpus() can still trigger a CPU hotplug operation, the device_hotplug_lock should be held. For reference, this was the deadlock with the old cpu_hotplug_begin() loop: chcpu (rescan) systemd-udevd echo 1 > /sys/../rescan -> smp_rescan_cpus() -> (*) get_online_cpus() (increases refcount) -> smp_add_present_cpu() (new CPU found) -> register_cpu() -> device_add() -> udev "add" event triggered -----------> udev rule sets CPU online -> echo 1 > /sys/.../online -> lock_device_hotplug_sysfs() (this is missing in rescan path) -> device_online() -> (**) device_lock(new CPU dev) -> cpu_up() -> cpu_hotplug_begin() (loops until refcount == 0) -> deadlock with (*) -> bus_probe_device() -> device_attach() -> device_lock(new CPU dev) -> deadlock with (**) Fix this by taking the device_hotplug_lock in the CPU rescan path. Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky Signed-off-by: Ben Hutchings

s390/vmlogrdr: fix IUCV buffer allocation

2017-03-16T02:26:34+00:00

commit 5457e03de918f7a3e294eb9d26a608ab8a579976 upstream. The buffer for iucv_message_receive() needs to be below 2 GB. In __iucv_message_receive(), the buffer address is casted to an u32, which would result in either memory corruption or an addressing exception when using addresses >= 2 GB. Fix this by using GFP_DMA for the buffer allocation. Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky Signed-off-by: Ben Hutchings

s390/con3270: fix insufficient space padding

2017-02-23T03:54:06+00:00

commit 6cd997db911f28f2510b771691270c52b63ed2e6 upstream. con3270 contains an optimisation that reduces the amount of data to be transmitted to the 3270 terminal by putting a Repeat to Address (RA) order into the data stream. The RA order itself takes up space, so con3270 only uses it if there's enough space left in the line buffer. Otherwise it just pads out the line manually. For lines that were _just_ short enough that the RA order still fit in the line buffer, the line was instead padded with an insufficient amount of spaces. This was caused by examining the size of the allocated line buffer rather than the length of the string to be displayed. For con3270_cline_end(), we just compare against the line length. For con3270_update_string() however that isn't available anymore, so we check whether the Repeat to Address order is present. Fixes: f51320a5 ("[PATCH] s390: new 3270 driver.") (tglx/history.git) Tested-by: Jing Liu Tested-by: Yang Chen Signed-off-by: Sascha Silbe Signed-off-by: Martin Schwidefsky Signed-off-by: Ben Hutchings

s390/con3270: fix use of uninitialised data

2017-02-23T03:54:06+00:00

commit c14f2aac7aa147861793eed9f41f91dd530f0be1 upstream. con3270 contains an optimisation that reduces the amount of data to be transmitted to the 3270 terminal by putting a Repeat to Address (RA) order into the data stream. The RA order itself takes up space, so con3270 only uses it if there's enough space left in the line buffer. Otherwise it just pads out the line manually. For lines too long to include the RA order, one byte was left uninitialised. This was caused by an off-by-one bug in the loop that pads out the line. Since the buffer is allocated from a common pool, the single byte left uninitialised contained some previous buffer content. Usually this was just a space or some character (which can result in clutter but is otherwise harmless). Sometimes, however, it was a Repeat to Address order, messing up the entire screen layout and causing the display to send the entire buffer content on every keystroke. Fixes: f51320a5 ("[PATCH] s390: new 3270 driver.") (tglx/history.git) Reported-by: Liu Jing Tested-by: Jing Liu Tested-by: Yang Chen Signed-off-by: Sascha Silbe Signed-off-by: Martin Schwidefsky Signed-off-by: Ben Hutchings

s390/sclp_ctl: fix potential information leak with /dev/sclp

2016-08-22T21:38:28+00:00

commit 532c34b5fbf1687df63b3fcd5b2846312ac943c6 upstream. The sclp_ctl_ioctl_sccb function uses two copy_from_user calls to retrieve the sclp request from user space. The first copy_from_user fetches the length of the request which is stored in the first two bytes of the request. The second copy_from_user gets the complete sclp request, but this copies the length field a second time. A malicious user may have changed the length in the meantime. Reported-by: Pengfei Wang Reviewed-by: Michael Holzheu Signed-off-by: Martin Schwidefsky Signed-off-by: Ben Hutchings

s390/sclp: fix compile error

2015-09-03T12:30:01+00:00

commit a313bdc5310dd807655d3ca3eb2219cd65dfe45a upstream. Fix this error when compiling with CONFIG_SMP=n and CONFIG_DYNAMIC_DEBUG=y: drivers/s390/char/sclp_early.c: In function 'sclp_read_info_early': drivers/s390/char/sclp_early.c:87:19: error: 'EBUSY' undeclared (first use in this function) } while (rc == -EBUSY); ^ Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky Cc: Stephen Powell Signed-off-by: Luis Henriques

s390/3215: fix tty output containing tabs

2015-01-05T10:15:52+00:00

commit e512d56c799517f33b301d81e9a5e0ebf30c2d1e upstream. git commit 37f81fa1f63ad38e16125526bb2769ae0ea8d332 "n_tty: do O_ONLCR translation as a single write" surfaced a bug in the 3215 device driver. In combination this broke tab expansion for tty ouput. The cause is an asymmetry in the behaviour of tty3215_ops->write vs tty3215_ops->put_char. The put_char function scans for '\t' but the write function does not. As the driver has logic for the '\t' expansion remove XTABS from c_oflag of the initial termios as well. Reported-by: Stephen Powell Signed-off-by: Martin Schwidefsky Cc: Ben Hutchings Signed-off-by: Luis Henriques

s390/3215: fix hanging console issue

2015-01-05T10:15:24+00:00

commit 26d766c60f4ea08cd14f0f3435a6db3d6cc2ae96 upstream. The ccw_device_start in raw3215_start_io can fail. raw3215_try_io does not check if the request could be started and removes any pending timer. This can leave the system in a hanging state. Check for pending request after raw3215_start_io and start a timer if necessary. Signed-off-by: Martin Schwidefsky Cc: Ben Hutchings Signed-off-by: Luis Henriques

s390/3270: correct size detection with the read-partition command

2014-07-16T08:48:10+00:00

The size detection for 3270 terminals with the read-partition command is broken. The raw3270_reset_device_cb function clears the init_data array, but if raw3270_writesf_readpart has been called the read-partition command is queued which needs the init_data array. In this case the size detection will fail and the invalid command does funny things to the terminal. Signed-off-by: Martin Schwidefsky

s390: avoid format strings leaking into names

2014-06-11T08:13:27+00:00

This makes sure format strings can't accidentally leak into kernel interface names. Signed-off-by: Kees Cook Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky