linux-toradex.git/ipc/sem.c, branch v5.5-rc7

ipc/sem.c: convert to use built-in RCU list checking

2019-09-26T00:51:41+00:00

CONFIG_PROVE_RCU_LIST requires list_for_each_entry_rcu() to pass a lockdep
expression if using srcu or locking for protection.  It can only check
regular RCU protection, all other protection needs to be passed as lockdep
expression.

Link: http://lkml.kernel.org/r/20190830231817.76862-2-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) 
Cc: Arnd Bergmann 
Cc: Bjorn Helgaas 
Cc: Catalin Marinas 
Cc: "Gustavo A. R. Silva" 
Cc: Jonathan Derrick 
Cc: Keith Busch 
Cc: Lorenzo Pieralisi 
Cc: "Paul E. McKenney" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc/sem.c: replace kvmalloc/memset with kvzalloc and use struct_size

2019-03-08T02:32:02+00:00

Use kvzalloc() instead of kvmalloc() and memset().

Also, make use of the struct_size() helper instead of the open-coded
version in order to avoid any potential type mistakes.

This code was detected with the help of Coccinelle.

Link: http://lkml.kernel.org/r/20190131214221.GA28930@embeddedor
Signed-off-by: Gustavo A. R. Silva 
Reviewed-by: Andrew Morton 
Cc: Davidlohr Bueso 
Cc: Manfred Spraul 
Cc: Kees Cook 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: annotate implicit fall through

2019-03-08T02:32:02+00:00

There is a plan to build the kernel with -Wimplicit-fallthrough and this
place in the code produced a warning (W=1).

This commit remove the following warning:

  ipc/sem.c:1683:6: warning: this statement may fall through [-Wimplicit-fallthrough=]

Link: http://lkml.kernel.org/r/20190114203608.18218-1-malat@debian.org
Signed-off-by: Mathieu Malaterre 
Reviewed-by: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

y2038: syscalls: rename y2038 compat syscalls

2019-02-06T23:13:27+00:00

A lot of system calls that pass a time_t somewhere have an implementation
using a COMPAT_SYSCALL_DEFINEx() on 64-bit architectures, and have
been reworked so that this implementation can now be used on 32-bit
architectures as well.

The missing step is to redefine them using the regular SYSCALL_DEFINEx()
to get them out of the compat namespace and make it possible to build them
on 32-bit architectures.

Any system call that ends in 'time' gets a '32' suffix on its name for
that version, while the others get a '_time32' suffix, to distinguish
them from the normal version, which takes a 64-bit time argument in the
future.

In this step, only 64-bit architectures are changed, doing this rename
first lets us avoid touching the 32-bit architectures twice.

Acked-by: Catalin Marinas 
Signed-off-by: Arnd Bergmann

ipc: rename old-style shmctl/semctl/msgctl syscalls

2019-01-25T16:22:50+00:00

The behavior of these system calls is slightly different between
architectures, as determined by the CONFIG_ARCH_WANT_IPC_PARSE_VERSION
symbol. Most architectures that implement the split IPC syscalls don't set
that symbol and only get the modern version, but alpha, arm, microblaze,
mips-n32, mips-n64 and xtensa expect the caller to pass the IPC_64 flag.

For the architectures that so far only implement sys_ipc(), i.e. m68k,
mips-o32, powerpc, s390, sh, sparc, and x86-32, we want the new behavior
when adding the split syscalls, so we need to distinguish between the
two groups of architectures.

The method I picked for this distinction is to have a separate system call
entry point: sys_old_*ctl() now uses ipc_parse_version, while sys_*ctl()
does not. The system call tables of the five architectures are changed
accordingly.

As an additional benefit, we no longer need the configuration specific
definition for ipc_parse_version(), it always does the same thing now,
but simply won't get called on architectures with the modern interface.

A small downside is that on architectures that do set
ARCH_WANT_IPC_PARSE_VERSION, we now have an extra set of entry points
that are never called. They only add a few bytes of bloat, so it seems
better to keep them compared to adding yet another Kconfig symbol.
I considered adding new syscall numbers for the IPC_64 variants for
consistency, but decided against that for now.

Signed-off-by: Arnd Bergmann

y2038: globally rename compat_time to old_time32

2018-08-27T12:48:48+00:00

Christoph Hellwig suggested a slightly different path for handling
backwards compatibility with the 32-bit time_t based system calls:

Rather than simply reusing the compat_sys_* entry points on 32-bit
architectures unchanged, we get rid of those entry points and the
compat_time types by renaming them to something that makes more sense
on 32-bit architectures (which don't have a compat mode otherwise),
and then share the entry points under the new name with the 64-bit
architectures that use them for implementing the compatibility.

The following types and interfaces are renamed here, and moved
from linux/compat_time.h to linux/time32.h:

old				new
---				---
compat_time_t			old_time32_t
struct compat_timeval		struct old_timeval32
struct compat_timespec		struct old_timespec32
struct compat_itimerspec	struct old_itimerspec32
ns_to_compat_timeval()		ns_to_old_timeval32()
get_compat_itimerspec64()	get_old_itimerspec32()
put_compat_itimerspec64()	put_old_itimerspec32()
compat_get_timespec64()		get_old_timespec32()
compat_put_timespec64()		put_old_timespec32()

As we already have aliases in place, this patch addresses only the
instances that are relevant to the system call interface in particular,
not those that occur in device drivers and other modules. Those
will get handled separately, while providing the 64-bit version
of the respective interfaces.

I'm not renaming the timex, rusage and itimerval structures, as we are
still debating what the new interface will look like, and whether we
will need a replacement at all.

This also doesn't change the names of the syscall entry points, which can
be done more easily when we actually switch over the 32-bit architectures
to use them, at that point we need to change COMPAT_SYSCALL_DEFINEx to
SYSCALL_DEFINEx with a new name, e.g. with a _time32 suffix.

Suggested-by: Christoph Hellwig 
Link: https://lore.kernel.org/lkml/20180705222110.GA5698@infradead.org/
Signed-off-by: Arnd Bergmann

ipc/util.c: further variable name cleanups

2018-08-22T17:52:52+00:00

The varable names got a mess, thus standardize them again:

id: user space id. Called semid, shmid, msgid if the type is known.
    Most functions use "id" already.
idx: "index" for the idr lookup
    Right now, some functions use lid, ipc_addid() already uses idx as
    the variable name.
seq: sequence number, to avoid quick collisions of the user space id
key: user space key, used for the rhash tree

Link: http://lkml.kernel.org/r/20180712185241.4017-12-manfred@colorfullife.com
Signed-off-by: Manfred Spraul 
Cc: Dmitry Vyukov 
Cc: Davidlohr Bueso 
Cc: Davidlohr Bueso 
Cc: Herbert Xu 
Cc: Kees Cook 
Cc: Michael Kerrisk 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: simplify ipc initialization

2018-08-22T17:52:52+00:00

Now that we know that rhashtable_init() will not fail, we can get rid of a
lot of the unnecessary cleanup paths when the call errored out.

[manfred@colorfullife.com: variable name added to util.h to resolve checkpatch warning]
Link: http://lkml.kernel.org/r/20180712185241.4017-11-manfred@colorfullife.com
Signed-off-by: Davidlohr Bueso 
Signed-off-by: Manfred Spraul 
Cc: Dmitry Vyukov 
Cc: Herbert Xu 
Cc: Kees Cook 
Cc: Michael Kerrisk 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: rename ipcctl_pre_down_nolock()

2018-08-22T17:52:51+00:00

Both the comment and the name of ipcctl_pre_down_nolock() are misleading:
The function must be called while holdling the rw semaphore.

Therefore the patch renames the function to ipcctl_obtain_check(): This
name matches the other names used in util.c:

- "obtain" function look up a pointer in the idr, without
  acquiring the object lock.
- The caller is responsible for locking.
- _check means that the sequence number is checked.

Link: http://lkml.kernel.org/r/20180712185241.4017-5-manfred@colorfullife.com
Signed-off-by: Manfred Spraul 
Reviewed-by: Davidlohr Bueso 
Cc: Davidlohr Bueso 
Cc: Dmitry Vyukov 
Cc: Herbert Xu 
Cc: Kees Cook 
Cc: Michael Kerrisk 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid()

2018-08-22T17:52:51+00:00

ipc_addid() is impossible to use:
- for certain failures, the caller must not use ipc_rcu_putref(),
  because the reference counter is not yet initialized.
- for other failures, the caller must use ipc_rcu_putref(),
  because parallel operations could be ongoing already.

The patch cleans that up, by initializing the refcount early, and by
modifying all callers.

The issues is related to the finding of
syzbot+2827ef6b3385deb07eaf@syzkaller.appspotmail.com: syzbot found an
issue with reading kern_ipc_perm.seq, here both read and write to already
released memory could happen.

Link: http://lkml.kernel.org/r/20180712185241.4017-4-manfred@colorfullife.com
Signed-off-by: Manfred Spraul 
Cc: Dmitry Vyukov 
Cc: Kees Cook 
Cc: Davidlohr Bueso 
Cc: Davidlohr Bueso 
Cc: Herbert Xu 
Cc: Michael Kerrisk 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds