linux.git/ipc, branch v5.1.16

ipc: prevent lockup on alloc_msg and free_msg

2019-06-15T09:52:50+00:00

[ Upstream commit d6a2946a88f524a47cc9b79279667137899db807 ]

msgctl10 of ltp triggers the following lockup When CONFIG_KASAN is
enabled on large memory SMP systems, the pages initialization can take a
long time, if msgctl10 requests a huge block memory, and it will block
rcu scheduler, so release cpu actively.

After adding schedule() in free_msg, free_msg can not be called when
holding spinlock, so adding msg to a tmp list, and free it out of
spinlock

  rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
  rcu:     Tasks blocked on level-1 rcu_node (CPUs 16-31): P32505
  rcu:     Tasks blocked on level-1 rcu_node (CPUs 48-63): P34978
  rcu:     (detected by 11, t=35024 jiffies, g=44237529, q=16542267)
  msgctl10        R  running task    21608 32505   2794 0x00000082
  Call Trace:
   preempt_schedule_irq+0x4c/0xb0
   retint_kernel+0x1b/0x2d
  RIP: 0010:__is_insn_slot_addr+0xfb/0x250
  Code: 82 1d 00 48 8b 9b 90 00 00 00 4c 89 f7 49 c1 ee 03 e8 59 83 1d 00 48 b8 00 00 00 00 00 fc ff df 4c 39 eb 48 89 9d 58 ff ff ff <41> c6 04 06 f8 74 66 4c 8d 75 98 4c 89 f1 48 c1 e9 03 48 01 c8 48
  RSP: 0018:ffff88bce041f758 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
  RAX: dffffc0000000000 RBX: ffffffff8471bc50 RCX: ffffffff828a2a57
  RDX: dffffc0000000000 RSI: dffffc0000000000 RDI: ffff88bce041f780
  RBP: ffff88bce041f828 R08: ffffed15f3f4c5b3 R09: ffffed15f3f4c5b3
  R10: 0000000000000001 R11: ffffed15f3f4c5b2 R12: 000000318aee9b73
  R13: ffffffff8471bc50 R14: 1ffff1179c083ef0 R15: 1ffff1179c083eec
   kernel_text_address+0xc1/0x100
   __kernel_text_address+0xe/0x30
   unwind_get_return_address+0x2f/0x50
   __save_stack_trace+0x92/0x100
   create_object+0x380/0x650
   __kmalloc+0x14c/0x2b0
   load_msg+0x38/0x1a0
   do_msgsnd+0x19e/0xcf0
   do_syscall_64+0x117/0x400
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

  rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
  rcu:     Tasks blocked on level-1 rcu_node (CPUs 0-15): P32170
  rcu:     (detected by 14, t=35016 jiffies, g=44237525, q=12423063)
  msgctl10        R  running task    21608 32170  32155 0x00000082
  Call Trace:
   preempt_schedule_irq+0x4c/0xb0
   retint_kernel+0x1b/0x2d
  RIP: 0010:lock_acquire+0x4d/0x340
  Code: 48 81 ec c0 00 00 00 45 89 c6 4d 89 cf 48 8d 6c 24 20 48 89 3c 24 48 8d bb e4 0c 00 00 89 74 24 0c 48 c7 44 24 20 b3 8a b5 41 <48> c1 ed 03 48 c7 44 24 28 b4 25 18 84 48 c7 44 24 30 d0 54 7a 82
  RSP: 0018:ffff88af83417738 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
  RAX: dffffc0000000000 RBX: ffff88bd335f3080 RCX: 0000000000000002
  RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88bd335f3d64
  RBP: ffff88af83417758 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000001 R11: ffffed13f3f745b2 R12: 0000000000000000
  R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000
   is_bpf_text_address+0x32/0xe0
   kernel_text_address+0xec/0x100
   __kernel_text_address+0xe/0x30
   unwind_get_return_address+0x2f/0x50
   __save_stack_trace+0x92/0x100
   save_stack+0x32/0xb0
   __kasan_slab_free+0x130/0x180
   kfree+0xfa/0x2d0
   free_msg+0x24/0x50
   do_msgrcv+0x508/0xe60
   do_syscall_64+0x117/0x400
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Davidlohr said:
 "So after releasing the lock, the msg rbtree/list is empty and new
  calls will not see those in the newly populated tmp_msg list, and
  therefore they cannot access the delayed msg freeing pointers, which
  is good. Also the fact that the node_cache is now freed before the
  actual messages seems to be harmless as this is wanted for
  msg_insert() avoiding GFP_ATOMIC allocations, and after releasing the
  info->lock the thing is freed anyway so it should not change things"

Link: http://lkml.kernel.org/r/1552029161-4957-1-git-send-email-lirongqing@baidu.com
Signed-off-by: Li RongQing 
Signed-off-by: Zhang Yu 
Reviewed-by: Davidlohr Bueso 
Cc: Manfred Spraul 
Cc: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2019-03-12T21:08:19+00:00

Pull vfs mount infrastructure updates from Al Viro:
 "The rest of core infrastructure; no new syscalls in that pile, but the
  old parts are switched to new infrastructure. At that point
  conversions of individual filesystems can happen independently; some
  are done here (afs, cgroup, procfs, etc.), there's also a large series
  outside of that pile dealing with NFS (quite a bit of option-parsing
  stuff is getting used there - it's one of the most convoluted
  filesystems in terms of mount-related logics), but NFS bits are the
  next cycle fodder.

  It got seriously simplified since the last cycle; documentation is
  probably the weakest bit at the moment - I considered dropping the
  commit introducing Documentation/filesystems/mount_api.txt (cutting
  the size increase by quarter ;-), but decided that it would be better
  to fix it up after -rc1 instead.

  That pile allows to do followup work in independent branches, which
  should make life much easier for the next cycle. fs/super.c size
  increase is unpleasant; there's a followup series that allows to
  shrink it considerably, but I decided to leave that until the next
  cycle"

* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits)
  afs: Use fs_context to pass parameters over automount
  afs: Add fs_context support
  vfs: Add some logging to the core users of the fs_context log
  vfs: Implement logging through fs_context
  vfs: Provide documentation for new mount API
  vfs: Remove kern_mount_data()
  hugetlbfs: Convert to fs_context
  cpuset: Use fs_context
  kernfs, sysfs, cgroup, intel_rdt: Support fs_context
  cgroup: store a reference to cgroup_ns into cgroup_fs_context
  cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper
  cgroup_do_mount(): massage calling conventions
  cgroup: stash cgroup_root reference into cgroup_fs_context
  cgroup2: switch to option-by-option parsing
  cgroup1: switch to option-by-option parsing
  cgroup: take options parsing into ->parse_monolithic()
  cgroup: fold cgroup1_mount() into cgroup1_get_tree()
  cgroup: start switching to fs_context
  ipc: Convert mqueue fs to fs_context
  proc: Add fs_context support to procfs
  ...

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

ipc: Convert mqueue fs to fs_context

2019-02-28T08:29:29+00:00

Convert the mqueue filesystem to use the filesystem context stuff.

Notes:

 (1) The relevant ipc namespace is selected in when the context is
     initialised (and it defaults to the current task's ipc namespace).
     The caller can override this before calling vfs_get_tree().

 (2) Rather than simply calling kern_mount_data(), mq_init_ns() and
     mq_internal_mount() create a context, adjust it and then do the rest
     of the mount procedure.

 (3) The lazy mqueue mounting on creation of a new namespace is retained
     from a previous patch, but the avoidance of sget() if no superblock
     yet exists is reverted and the superblock is again keyed on the
     namespace pointer.

     Yes, there was a performance gain in not searching the superblock
     hash, but it's only paid once per ipc namespace - and only if someone
     uses mqueue within that namespace, so I'm not sure it's worth it,
     especially as calling sget() allows avoidance of recursion.

Signed-off-by: David Howells 
Signed-off-by: Al Viro

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

ipc: introduce ksys_ipc()/compat_ksys_ipc() for s390

2019-01-18T08:33:18+00:00

The sys_ipc() and compat_ksys_ipc() functions are meant to only
be used from the system call table, not called by another function.

Introduce ksys_*() interfaces for this purpose, as we have done
for many other system calls.

Link: https://lore.kernel.org/lkml/20190116131527.2071570-3-arnd@arndb.de
Signed-off-by: Arnd Bergmann 
Reviewed-by: Heiko Carstens 
[heiko.carstens@de.ibm.com: compile fix for !CONFIG_COMPAT]
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

ipc: IPCMNI limit check for semmni

2018-10-31T15:54:14+00:00

For SysV semaphores, the semmni value is the last part of the 4-element
sem number array.  To make semmni behave in a similar way to msgmni and
shmmni, we can't directly use the _minmax handler.  Instead, a special sem
specific handler is added to check the last argument to make sure that it
is limited to the [0, IPCMNI] range.  An error will be returned if this is
not the case.

Link: http://lkml.kernel.org/r/1536352137-12003-3-git-send-email-longman@redhat.com
Signed-off-by: Waiman Long 
Reviewed-by: Davidlohr Bueso 
Cc: "Eric W. Biederman" 
Cc: Jonathan Corbet 
Cc: Kees Cook 
Cc: Luis R. Rodriguez 
Cc: Matthew Wilcox 
Cc: Takashi Iwai 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: IPCMNI limit check for msgmni and shmmni

2018-10-31T15:54:14+00:00

Patch series "ipc: IPCMNI limit check for *mni & increase that limit", v9.

The sysctl parameters msgmni, shmmni and semmni have an inherent limit of
IPC_MNI (32k).  However, users may not be aware of that because they can
write a value much higher than that without getting any error or
notification.  Reading the parameters back will show the newly written
values which are not real.

The real IPCMNI limit is now enforced to make sure that users won't put in
an unrealistic value.  The first 2 patches enforce the limits.

There are also users out there requesting increase in the IPCMNI value.
The last 2 patches attempt to do that by using a boot kernel parameter
"ipcmni_extend" to increase the IPCMNI limit from 32k to 8M if the users
really want the extended value.

This patch (of 4):

A user can write arbitrary integer values to msgmni and shmmni sysctl
parameters without getting error, but the actual limit is really IPCMNI
(32k).  This can mislead users as they think they can get a value that is
not real.

The right limits are now set for msgmni and shmmni so that the users will
become aware if they set a value outside of the acceptable range.

Link: http://lkml.kernel.org/r/1536352137-12003-2-git-send-email-longman@redhat.com
Signed-off-by: Waiman Long 
Acked-by: Luis R. Rodriguez 
Reviewed-by: Davidlohr Bueso 
Cc: Kees Cook 
Cc: Jonathan Corbet 
Cc: Matthew Wilcox 
Cc: "Eric W. Biederman" 
Cc: Takashi Iwai 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds