1. sys_getpgid() needs rcu_read_lock() to derive the pgrp _nr, even if
the task is current, otherwise we can race with another thread which
does sys_setpgid().
2. Use rcu_read_lock() instead of tasklist_lock when pid != 0, make sure
that we don't use the NULL pid if the task exits right after successful
find_task_by_vpid().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pids: sys_getsid: fix unsafe *pid usage, fix possible 0 instead of -ESRCH
1. sys_getsid() needs rcu_read_lock() to derive the session _nr, even if
the task is current, otherwise we can race with another thread which
does sys_setsid().
2. The task can exit between find_task_by_vpid() and task_session_vnr(),
in that unlikely case sys_getsid() returns 0 instead of -ESRCH.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Without tasklist_lock held task_session()/task_pgrp() can return NULL if the
caller races with setprgp()/setsid() which does detach_pid() + attach_pid().
This can happen even if task == current.
Intoduce the new helper, change_pid(), which should be used instead. This way
the caller always sees the special pid != NULL, either old or new.
Also change the prototype of attach_pid(), it always returns 0 and nobody
check the returned value.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pids: de_thread: don't clear session/pgrp pids for the old leader
Based on Eric W. Biederman's idea.
Unless task == current, without tasklist_lock held task_session()/task_pgrp()
can return NULL if the caller races with de_thread() which switches the group
leader.
Change transfer_pid() to not clear old->pids[type].pid for the old leader.
This means that its .pid can point to "nowhere", but this is already true for
sub-threads, and the old leader is not group_leader() any longer. IOW, with
or without this change we can't trust task's special pids unless it is the
group leader.
Pavel Emelyanov [Wed, 30 Apr 2008 07:54:23 +0000 (00:54 -0700)]
Use find_task_by_vpid in taskstats
The pid to lookup a task by is passed inside taskstats code via genetlink
message.
Since netlink packets are now processed in the context of the sending task,
this is correct to lookup the task with find_task_by_vpid() here.
Besides, I fix the call to fill_pid() from taskstats_exit(), since the
tsk->pid is not required in fill_pid() in this case, and the pid field on
task_struct is going to be deprecated as well.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@engr.sgi.com> Cc: Jonathan Lim <jlim@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Factor out the code used to allocate/free a pts index into new interfaces,
devpts_new_index() and devpts_kill_index(). This localizes the external data
structures used in managing the pts indices.
[akpm@linux-foundation.org: undo accidental mutex2sem conversion] Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:54:19 +0000 (00:54 -0700)]
char serial: switch drivers to ioremap_nocache
Simple search/replace except for synclink.c where I noticed a real bug and
fixed it too. It was doing NULL + offset, then checking for NULL if the remap
failed.
Signed-off-by: Alan Cox <alan@redhat.com> Cc: Paul Fulghum <paulkf@microgate.com> Acked-by: Jiri Slaby <jirislaby@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:54:18 +0000 (00:54 -0700)]
tty: add throttle/unthrottle helpers
Something Arjan suggested which allows us to clean up the code nicely
Signed-off-by: Alan Cox <alan@redhat.com> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:54:14 +0000 (00:54 -0700)]
strip: Fix up strip for the new order
- Use the tty baud functions
- Call driver termios methods directly holding the right locking
- Check for a write method
Signed-off-by: Alan Cox <alan@redhat.com> Cc: David S. Miller <davem@davemloft.net> Cc: Jeff Garzik <jeff@garzik.org> Cc: "John W. Linville" <linville@tuxdriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:54:11 +0000 (00:54 -0700)]
serial: switch the serial core to int put_char methods
Signed-off-by: Alan Cox <alan@redhat.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:54:10 +0000 (00:54 -0700)]
pty: prepare for tty->ops changes
We are about to change the tty layer to avoid keeping private copies of all
the methods in each tty. We have to update the pty layer first as it
currently patches the ioctl method according to the tty type. Use multiple
tty operations sets instead.
Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename defines to be in RIO* namespace to not to collide with other defines in
tree. This broke (as akpm correctly pointed out) some allmodconfig builds,
e.g. on ppc:
In file included from drivers/char/rio/rio_linux.c:81:
drivers/char/rio/cirrus.h:202:1: warning: "COMPLETE" redefined
In file included from include/net/netns/ipv4.h:8,
from include/net/net_namespace.h:13,
from include/linux/seq_file.h:7,
from include/asm/machdep.h:12,
from include/asm/pci.h:17,
from include/linux/pci.h:951,
from drivers/char/rio/rio_linux.c:50:
include/net/inet_frag.h:28:1: warning: this is the location of the previous definition
- remove i2os.h -- there was only macro to macro renaming or useless
stuff
- remove another uselless stuf (NULLFUNC, NULLPTR, YES, NO)
- use outb/inb directly
- use locking functions directly
- don't define another ROUNDUP, use roundup(x, 2) instead
- some comments and whitespace cleanup
- remove some commented crap
- prepend the rest by I2 prefix to not collide with rest of the world
like in following output (pointed out by akpm)
In file included from drivers/char/ip2/ip2main.c:128:
drivers/char/ip2/i2ellis.h:608:1: warning: "COMPLETE" redefined
In file included from include/net/netns/ipv4.h:8,
from include/net/net_namespace.h:13,
from include/linux/seq_file.h:7,
from include/asm/machdep.h:12,
from include/asm/pci.h:17,
from include/linux/pci.h:951,
from drivers/char/ip2/ip2main.c:95:
include/net/inet_frag.h:28:1: warning: this is the location of the previous definition
Harvey Harrison [Wed, 30 Apr 2008 07:53:52 +0000 (00:53 -0700)]
epca.c: static functions and integer as NULL pointer fixes
drivers/char/epca.c:926:28: warning: Using plain integer as NULL pointer
drivers/char/epca.c:1841:2: warning: Using plain integer as NULL pointer
Forward declarations were already marked static, mark the definitions too.
drivers/char/epca.c:2493:6: warning: symbol 'digi_send_break' was not declared. Should it be static?
drivers/char/epca.c:2881:12: warning: symbol 'init_PCI' was not declared. Should it be static?
[akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Harvey Harrison [Wed, 30 Apr 2008 07:53:52 +0000 (00:53 -0700)]
cyclades.c: fix sparse shadowed variable warnings
Nested min() macros.
drivers/char/cyclades.c:2750:7: warning: symbol '_x' shadows an earlier one
drivers/char/cyclades.c:2750:7: originally declared here
drivers/char/cyclades.c:2750:7: warning: symbol '_x' shadows an earlier one
drivers/char/cyclades.c:2750:7: originally declared here
drivers/char/cyclades.c:2750:7: warning: symbol '_y' shadows an earlier one
drivers/char/cyclades.c:2750:7: originally declared here
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Harvey Harrison [Wed, 30 Apr 2008 07:53:51 +0000 (00:53 -0700)]
char: rocket.c: fix sparse variable shadowing and int as NULL pointer
Nested min() macros shadow _x, separate into two lines.
drivers/char/rocket.c:451:7: warning: symbol '_x' shadows an earlier one
drivers/char/rocket.c:451:7: originally declared here
drivers/char/rocket.c:451:7: warning: symbol '_x' shadows an earlier one
drivers/char/rocket.c:451:7: originally declared here
drivers/char/rocket.c:451:7: warning: symbol '_y' shadows an earlier one
drivers/char/rocket.c:451:7: originally declared here
drivers/char/rocket.c:1754:7: warning: symbol '_x' shadows an earlier one
drivers/char/rocket.c:1754:7: originally declared here
drivers/char/rocket.c:1754:7: warning: symbol '_x' shadows an earlier one
drivers/char/rocket.c:1754:7: originally declared here
drivers/char/rocket.c:1754:7: warning: symbol '_y' shadows an earlier one
drivers/char/rocket.c:1754:7: originally declared here
drivers/char/rocket.c:1751:20: warning: Using plain integer as NULL pointer
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Harvey Harrison [Wed, 30 Apr 2008 07:53:50 +0000 (00:53 -0700)]
char: fix sparse shadowed variable warnings in esp.c
flags only use was in spin_lock_irqsave/spin_lock_irgrestore pairs, no
need to redeclare for each one.
drivers/char/esp.c:1599:17: warning: symbol 'flags' shadows an earlier one
drivers/char/esp.c:1517:16: originally declared here
drivers/char/esp.c:1615:17: warning: symbol 'flags' shadows an earlier one
drivers/char/esp.c:1517:16: originally declared here
drivers/char/esp.c:1631:17: warning: symbol 'flags' shadows an earlier one
drivers/char/esp.c:1517:16: originally declared here
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- moxa_flush_chars -- no code; ldics handle this well
- moxa_put_char -- only wrapper to moxa_write (same code), tty does this
the same way if tty->driver->put_char is NULL
- add locking to open/close/hangup and ioctl (tiocm)
- add pci hot-un-plug support (hangup on board remove, wait for openers)
- cleanup block_till_ready
- move close code common to close/hangup into separate function to be
able to call it from open when hangup occurs while block_till_ready
- let ldisc flush on tty layer, it will do it after we return
- merge 2 timers into one -- one can handle the emptywait as good as the other
- merge 2 separated poll functions into one, this allows handle the actions
directly and simplifies the code
- allow stats only for sys_admin
- move TCSBRK* processing to .break_ctl tty op
- let TIOCGSOFTCAR and TIOCSSOFTCAR be processed by ldisc
- remove MOXA_GET_MAJOR, MOXA_GET_CUMAJOR
- fix jiffies subtraction by time_after
- move moxa ioctl numbers into the header; still not exported to userspace,
needs _IOC and 32/64 compat cleanup anyways
The only relevant sign of port being ready is its board->ready since now.
Remove all other flags for this purpose which are set almost on the same
place. Move ports inside the board to be sure that nobody will grab reference
to the port without being sure that it exists.
- request region before remapping pci io space
- use ioremap, iounmap istead of iomap interface, because we use
readX/writeX for accessing this space because of isa support
Static ISA field is empty and probably will never be filled in, remove it.
The driver still supports ISA cards passed through module parameter. This
actually fixes one bug inside the initialization of module-param passed cards
initialization.
Alan Cox [Wed, 30 Apr 2008 07:53:34 +0000 (00:53 -0700)]
tty_ioctl: soft carrier handling
First cut at moving the soft carrier handling knowledge entirely into the core
code. One or two drivers still needed to snoop these functions to track
CLOCAL internally. Instead make TIOCSSOFTCAR generate the same driver calls
as other termios ioctls changing the clocal flag. This allows us to remove
any driver knowledge and special casing. Also while we are at it we can fix
the error handling.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joe Peterson [Wed, 30 Apr 2008 07:53:30 +0000 (00:53 -0700)]
Resume TTY on SUSP and fix CRNL order in N_TTY line discipline
Refine these behaviors in the N_TTY line discipline:
1) Handle the signal characters consistently when received in a stopped TTY
so that SUSP (typically ctrl-Z) behaves like INTR and QUIT in resuming a
stopped TTY.
2) Adjust the order in which the IGNCR/ICRNL/INLCR processing is applied to
be more logical and consistent with the behavior of other Unix systems.
Signed-off-by: Joe Peterson <joe@skyrush.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:53:30 +0000 (00:53 -0700)]
redo locking of tty->pgrp
Historically tty->pgrp and friends were pid_t and the code "knew" they were
safe. The change to pid structs opened up a few races and the removal of the
BKL in places made them quite hittable. We put tty->pgrp under the ctrl_lock
for the tty.
Signed-off-by: Alan Cox <alan@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:53:29 +0000 (00:53 -0700)]
tty: BKL pushdown
- Push the BKL down into the line disciplines
- Switch the tty layer to unlocked_ioctl
- Introduce a new ctrl_lock spin lock for the control bits
- Eliminate much of the lock_kernel use in n_tty
- Prepare to (but don't yet) call the drivers with the lock dropped
on the paths that historically held the lock
BKL now primarily protects open/close/ldisc change in the tty layer
[jirislaby@gmail.com: a couple of fixes] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:53:28 +0000 (00:53 -0700)]
serial_core: Prepare for BKL push down
Instead of checking for the BKL in these methods, take it ourselves. That
avoids propogating it into the serial drivers and we can then fix them later
on.
Signed-off-by: Alan Cox <alan@redhat.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:53:26 +0000 (00:53 -0700)]
vt_ioctl: Prepare for BKL push down
This one could do with some eyeballs on it. In theory it simply wraps the
ioctl handler in lock/unlock_kernel ready for the lock/unlocks to be pushed
into specific switch values. To do that means changing the code to return via
a common exit path not all over the place as it does now, hence the big diff
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:53:25 +0000 (00:53 -0700)]
viocons: BKL locking
For some weird reason I can't ascertain (translation "I think its
broken") the viocons driver calls directly into the n_tty ldisc code even
if another ldisc is in use. It'll probably break if you do that but I'm
just fixing the locking and adding a comment that its horked.
Signed-off-by: Alan Cox <alan@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alan Cox [Wed, 30 Apr 2008 07:53:17 +0000 (00:53 -0700)]
epca: lock_kernel push down
Prepare epca for removing the lock from above. Most of epca is internally
locked so we can trivially push it down to a few bits of code. Drop the TIOCG/SSOFTCAR handling as that is done *properly* with locks by the mid layer.
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Afaics, currently there are no kernel problems with ptracing init, it can't
lose SIGNAL_UNKILLABLE flag and be killed/stopped by accident.
The ability to strace/debug init can be very useful if you try to figure out
why it does not work as expected.
However, admin should know what he does, "gdb /sbin/init 1" stops init, it
can't reap orphaned zombies or take care of /etc/inittab until continued. It
is even possible to crash init (and thus the whole system) if you wish,
ptracer has full control.
See also the long discussion: http://marc.info/?t=120628018600001
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Acked-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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