[Issue]
Currently, a variable name, which identifies each entry, consists of type, id and ctime.
But if multiple events happens in a short time, a second/third event may fail to log because
efi_pstore can't distinguish each event with current variable name.
[Solution]
A reasonable way to identify all events precisely is introducing a sequence counter to
the variable name.
The sequence counter has already supported in a pstore layer with "oopscount".
So, this patch adds it to a variable name.
Also, it is passed to read/erase callbacks of platform drivers in accordance with
the modification of the variable name.
<before applying this patch>
a variable name of first event: dump-type0-1-12345678
a variable name of second event: dump-type0-1-12345678
type:0
id:1
ctime:12345678
If multiple events happen in a short time, efi_pstore can't distinguish them because
variable names are same among them.
<after applying this patch>
it can be distinguishable by adding a sequence counter as follows.
a variable name of first event: dump-type0-1-1-12345678
a variable name of Second event: dump-type0-1-2-12345678
type:0
id:1
sequence counter: 1(first event), 2(second event)
ctime:12345678
In case of a write callback executed in pstore_console_write(), "0" is added to
an argument of the write callback because it just logs all kernel messages and
doesn't need to care about multiple events.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
[Issue]
Currently, a variable name, which is used to identify each log entry, consists of type,
id and ctime. But an erase callback does not use ctime.
If efi_pstore supported just one log, type and id were enough.
However, in case of supporting multiple logs, it doesn't work because
it can't distinguish each entry without ctime at erasing time.
<Example>
As you can see below, efi_pstore can't differentiate first event from second one without ctime.
a variable name of first event: dump-type0-1-12345678
a variable name of second event: dump-type0-1-23456789
type:0
id:1
ctime:12345678, 23456789
[Solution]
This patch adds ctime to an argument of an erase callback.
It works across reboots because ctime of pstore means the date that the record was originally stored.
To do this, efi_pstore saves the ctime to variable name at writing time and passes it to pstore
at reading time.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Pull MTD fixes from David Woodhouse:
"The most important part of this is that it fixes a regression in
Samsung NAND chip detection, introduced by some rework which went into
3.7. The initial fix wasn't quite complete, so it's in two parts. In
fact the first part is committed twice (Artem committed his own copy
of the same patch) and I've merged Artem's tree into mine which
already had that fix.
I'd have recommitted that to make it somewhat cleaner, but figured by
this point in the release cycle it was better to merge *exactly* the
commits which have been in linux-next.
If I'd recommitted, I'd also omit the sparse warning fix. But it's
there, and it's harmless — just marking one function as 'static' in
onenand code.
This also includes a couple more fixes for stable: an AB-BA deadlock
in JFFS2, and an invalid range check in slram."
* tag 'for-linus-20121123' of git://git.infradead.org/mtd-2.6:
mtd: nand: fix Samsung SLC detection regression
mtd: nand: fix Samsung SLC NAND identification regression
jffs2: Fix lock acquisition order bug in jffs2_write_begin
mtd: onenand: Make flexonenand_set_boundary static
mtd: slram: invalid checking of absolute end address
mtd: ofpart: Fix incorrect NULL check in parse_ofoldpart_partitions()
mtd: nand: fix Samsung SLC NAND identification regression
Pull reiserfs and ext3 fixes from Jan Kara:
"Fixes of reiserfs deadlocks when quotas are enabled (locking there was
completely busted by BKL conversion) and also one small ext3 fix in
the trim interface."
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
ext3: Avoid underflow of in ext3_trim_fs()
reiserfs: Move quota calls out of write lock
reiserfs: Protect reiserfs_quota_write() with write lock
reiserfs: Protect reiserfs_quota_on() with write lock
reiserfs: Fix lock ordering during remount
Currently if len argument in ext3_trim_fs() is smaller than one block,
the 'end' variable underflow. Avoid that by returning EINVAL if len is
smaller than file system block.
Also remove useless unlikely().
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Calls into highlevel quota code cannot happen under the write lock. These
calls take dqio_mutex which ranks above write lock. So drop write lock
before calling back into quota code.
CC: stable@vger.kernel.org # >= 3.0
Signed-off-by: Jan Kara <jack@suse.cz>
Calls into reiserfs journalling code and reiserfs_get_block() need to
be protected with write lock. We remove write lock around calls to high
level quota code in the next patch so these paths would suddently become
unprotected.
CC: stable@vger.kernel.org # >= 3.0
Signed-off-by: Jan Kara <jack@suse.cz>
In reiserfs_quota_on() we do quite some work - for example unpacking
tail of a quota file. Thus we have to hold write lock until a moment
we call back into the quota code.
CC: stable@vger.kernel.org # >= 3.0
Signed-off-by: Jan Kara <jack@suse.cz>
When remounting reiserfs dquot_suspend() or dquot_resume() can be called.
These functions take dqonoff_mutex which ranks above write lock so we have
to drop it before calling into quota code.
CC: stable@vger.kernel.org # >= 3.0
Signed-off-by: Jan Kara <jack@suse.cz>
If the FAN_Q_OVERFLOW bit set in event->mask, the fanotify event
metadata will not contain a valid file descriptor, but
copy_event_to_user() didn't check for that, and unconditionally does a
fd_install() on the file descriptor.
Which in turn will cause a BUG_ON() in __fd_install().
Introduced by commit 352e3b2492 ("fanotify: sanitize failure exits in
copy_event_to_user()")
Mea culpa - missed that path ;-/
Reported-by: Alex Shi <lkml.alex@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull misc VFS fixes from Al Viro:
"Remove a bogus BUG_ON() that can trigger spuriously + alpha bits of
do_mount() constification I'd missed during the merge window."
This pull request came in a week ago, I missed it for some reason.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
kill bogus BUG_ON() in do_close_on_exec()
missing const in alpha callers of do_mount()
Pull xfs bugfixes from Ben Myers:
- fix attr tree double split corruption
- fix broken error handling in xfs_vm_writepage
- drop buffer io reference when a bad bio is built
* tag 'for-linus-v3.7-rc7' of git://oss.sgi.com/xfs/xfs:
xfs: drop buffer io reference when a bad bio is built
xfs: fix broken error handling in xfs_vm_writepage
xfs: fix attr tree double split corruption
Error handling in xfs_buf_ioapply_map() does not handle IO reference
counts correctly. We increment the b_io_remaining count before
building the bio, but then fail to decrement it in the failure case.
This leads to the buffer never running IO completion and releasing
the reference that the IO holds, so at unmount we can leak the
buffer. This leak is captured by this assert failure during unmount:
XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0, file: fs/xfs/xfs_mount.c, line: 273
This is not a new bug - the b_io_remaining accounting has had this
problem for a long, long time - it's just very hard to get a
zero length bio being built by this code...
Further, the buffer IO error can be overwritten on a multi-segment
buffer by subsequent bio completions for partial sections of the
buffer. Hence we should only set the buffer error status if the
buffer is not already carrying an error status. This ensures that a
partial IO error on a multi-segment buffer will not be lost. This
part of the problem is a regression, however.
cc: <stable@vger.kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
When we shut down the filesystem, it might first be detected in
writeback when we are allocating a inode size transaction. This
happens after we have moved all the pages into the writeback state
and unlocked them. Unfortunately, if we fail to set up the
transaction we then abort writeback and try to invalidate the
current page. This then triggers are BUG() in block_invalidatepage()
because we are trying to invalidate an unlocked page.
Fixing this is a bit of a chicken and egg problem - we can't
allocate the transaction until we've clustered all the pages into
the IO and we know the size of it (i.e. whether the last block of
the IO is beyond the current EOF or not). However, we don't want to
hold pages locked for long periods of time, especially while we lock
other pages to cluster them into the write.
To fix this, we need to make a clear delineation in writeback where
errors can only be handled by IO completion processing. That is,
once we have marked a page for writeback and unlocked it, we have to
report errors via IO completion because we've already started the
IO. We may not have submitted any IO, but we've changed the page
state to indicate that it is under IO so we must now use the IO
completion path to report errors.
To do this, add an error field to xfs_submit_ioend() to pass it the
error that occurred during the building on the ioend chain. When
this is non-zero, mark each ioend with the error and call
xfs_finish_ioend() directly rather than building bios. This will
immediately push the ioends through completion processing with the
error that has occurred.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
In certain circumstances, a double split of an attribute tree is
needed to insert or replace an attribute. In rare situations, this
can go wrong, leaving the attribute tree corrupted. In this case,
the attr being replaced is the last attr in a leaf node, and the
replacement is larger so doesn't fit in the same leaf node.
When we have the initial condition of a node format attribute
btree with two leaves at index 1 and 2. Call them L1 and L2. The
leaf L1 is completely full, there is not a single byte of free space
in it. L2 is mostly empty. The attribute being replaced - call it X
- is the last attribute in L1.
The way an attribute replace is executed is that the replacement
attribute - call it Y - is first inserted into the tree, but has an
INCOMPLETE flag set on it so that list traversals ignore it. Once
this transaction is committed, a second transaction it run to
atomically mark Y as COMPLETE and X as INCOMPLETE, so that a
traversal will now find Y and skip X. Once that transaction is
committed, attribute X is then removed.
So, the initial condition is:
+--------+ +--------+
| L1 | | L2 |
| fwd: 2 |---->| fwd: 0 |
| bwd: 0 |<----| bwd: 1 |
| fsp: 0 | | fsp: N |
|--------| |--------|
| attr A | | attr 1 |
|--------| |--------|
| attr B | | attr 2 |
|--------| |--------|
.......... ..........
|--------| |--------|
| attr X | | attr n |
+--------+ +--------+
So now we go to replace X, and see that L1:fsp = 0 - it is full so
we can't insert Y in the same leaf. So we record the the location of
attribute X so we can track it for later use, then we split L1 into
L1 and L3 and reblance across the two leafs. We end with:
+--------+ +--------+ +--------+
| L1 | | L3 | | L2 |
| fwd: 3 |---->| fwd: 2 |---->| fwd: 0 |
| bwd: 0 |<----| bwd: 1 |<----| bwd: 3 |
| fsp: M | | fsp: J | | fsp: N |
|--------| |--------| |--------|
| attr A | | attr X | | attr 1 |
|--------| +--------+ |--------|
| attr B | | attr 2 |
|--------| |--------|
.......... ..........
|--------| |--------|
| attr W | | attr n |
+--------+ +--------+
And we track that the original attribute is now at L3:0.
We then try to insert Y into L1 again, and find that there isn't
enough room because the new attribute is larger than the old one.
Hence we have to split again to make room for Y. We end up with
this:
+--------+ +--------+ +--------+ +--------+
| L1 | | L4 | | L3 | | L2 |
| fwd: 4 |---->| fwd: 3 |---->| fwd: 2 |---->| fwd: 0 |
| bwd: 0 |<----| bwd: 1 |<----| bwd: 4 |<----| bwd: 3 |
| fsp: M | | fsp: J | | fsp: J | | fsp: N |
|--------| |--------| |--------| |--------|
| attr A | | attr Y | | attr X | | attr 1 |
|--------| + INCOMP + +--------+ |--------|
| attr B | +--------+ | attr 2 |
|--------| |--------|
.......... ..........
|--------| |--------|
| attr W | | attr n |
+--------+ +--------+
And now we have the new (incomplete) attribute @ L4:0, and the
original attribute at L3:0. At this point, the first transaction is
committed, and we move to the flipping of the flags.
This is where we are supposed to end up with this:
+--------+ +--------+ +--------+ +--------+
| L1 | | L4 | | L3 | | L2 |
| fwd: 4 |---->| fwd: 3 |---->| fwd: 2 |---->| fwd: 0 |
| bwd: 0 |<----| bwd: 1 |<----| bwd: 4 |<----| bwd: 3 |
| fsp: M | | fsp: J | | fsp: J | | fsp: N |
|--------| |--------| |--------| |--------|
| attr A | | attr Y | | attr X | | attr 1 |
|--------| +--------+ + INCOMP + |--------|
| attr B | +--------+ | attr 2 |
|--------| |--------|
.......... ..........
|--------| |--------|
| attr W | | attr n |
+--------+ +--------+
But that doesn't happen properly - the attribute tracking indexes
are not pointing to the right locations. What we end up with is both
the old attribute to be removed pointing at L4:0 and the new
attribute at L4:1. On a debug kernel, this assert fails like so:
XFS: Assertion failed: args->index2 < be16_to_cpu(leaf2->hdr.count), file: fs/xfs/xfs_attr_leaf.c, line: 2725
because the new attribute location does not exist. On a production
kernel, this goes unnoticed and the code proceeds ahead merrily and
removes L4 because it thinks that is the block that is no longer
needed. This leaves the hash index node pointing to entries
L1, L4 and L2, but only blocks L1, L3 and L2 to exist. Further, the
leaf level sibling list is L1 <-> L4 <-> L2, but L4 is now free
space, and so everything is busted. This corruption is caused by the
removal of the old attribute triggering a join - it joins everything
correctly but then frees the wrong block.
xfs_repair will report something like:
bad sibling back pointer for block 4 in attribute fork for inode 131
problem with attribute contents in inode 131
would clear attr fork
bad nblocks 8 for inode 131, would reset to 3
bad anextents 4 for inode 131, would reset to 0
The problem lies in the assignment of the old/new blocks for
tracking purposes when the double leaf split occurs. The first split
tries to place the new attribute inside the current leaf (i.e.
"inleaf == true") and moves the old attribute (X) to the new block.
This sets up the old block/index to L1:X, and newly allocated
block to L3:0. It then moves attr X to the new block and tries to
insert attr Y at the old index. That fails, so it splits again.
With the second split, the rebalance ends up placing the new attr in
the second new block - L4:0 - and this is where the code goes wrong.
What is does is it sets both the new and old block index to the
second new block. Hence it inserts attr Y at the right place (L4:0)
but overwrites the current location of the attr to replace that is
held in the new block index (currently L3:0). It over writes it with
L4:1 - the index we later assert fail on.
Hopefully this table will show this in a foramt that is a bit easier
to understand:
Split old attr index new attr index
vanilla patched vanilla patched
before 1st L1:26 L1:26 N/A N/A
after 1st L3:0 L3:0 L1:26 L1:26
after 2nd L4:0 L3:0 L4:1 L4:0
^^^^ ^^^^
wrong wrong
The fix is surprisingly simple, for all this analysis - just stop
the rebalance on the out-of leaf case from overwriting the new attr
index - it's already correct for the double split case.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
This is mostly a revert of 01dc52ebdf ("oom: remove deprecated oom_adj")
from Davidlohr Bueso.
It reintroduces /proc/pid/oom_adj for backwards compatibility with earlier
kernels. It simply scales the value linearly when /proc/pid/oom_score_adj
is written.
The major difference is that its scheduled removal is no longer included
in Documentation/feature-removal-schedule.txt. We do warn users with a
single printk, though, to suggest the more powerful and supported
/proc/pid/oom_score_adj interface.
Reported-by: Artem S. Tashkinov <t.artem@lycos.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull UBIFS fixes from Artem Bityutskiy:
"Two patches which fix a problem reported by several people in the
past, but only fixed now because no one gave enough material for
debugging.
Anyway, these fix the problem that sometimes after a power cut the
file-system is not mountable with the following symptom:
grab_empty_leb: could not find an empty LEB
The fixes make the file-system mountable again."
* tag 'upstream-3.7-rc6' of git://git.infradead.org/linux-ubifs:
UBIFS: fix mounting problems after power cuts
UBIFS: introduce categorized lprops counter
Passing a NULL id causes a NULL pointer deference in writers such as
erst_writer and efi_pstore_write because they expect to update this id.
Pass a dummy id instead.
This avoids a cascade of oopses caused when the initial
pstore_console_write passes a null which in turn causes writes to the
console causing further oopses in subsequent pstore_console_write calls.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
It can be legitimately triggered via procfs access. Now, at least
2 of 3 of get_files_struct() callers in procfs are useless, but
when and if we get rid of those we can always add WARN_ON() here.
BUG_ON() at that spot is simply wrong.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull cifs fixes from Jeff Layton.
* 'for-linus' of git://git.samba.org/sfrench/cifs-2.6:
cifs: Do not lookup hashed negative dentry in cifs_atomic_open
cifs: fix potential buffer overrun in cifs.idmap handling code
jffs2_write_begin() first acquires the page lock, then f->sem. This
causes an AB-BA deadlock with jffs2_garbage_collect_live(), which first
acquires f->sem, then the page lock:
jffs2_garbage_collect_live
mutex_lock(&f->sem) (A)
jffs2_garbage_collect_dnode
jffs2_gc_fetch_page
read_cache_page_async
do_read_cache_page
lock_page(page) (B)
jffs2_write_begin
grab_cache_page_write_begin
find_lock_page
lock_page(page) (B)
mutex_lock(&f->sem) (A)
We fix this by restructuring jffs2_write_begin() to take f->sem before
the page lock. However, we make sure that f->sem is not held when
calling jffs2_reserve_space(), as this is not permitted by the locking
rules.
The deadlock above was observed multiple times on an SoC with a dual
ARMv7 (Cortex-A9), running the long-term 3.4.11 kernel; it occurred
when using scp to copy files from a host system to the ARM target
system. The fix was heavily tested on the same target system.
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Betker <thomas.betker@rohde-schwarz.com>
Acked-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Merge misc fixes from Andrew Morton:
"Five fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (5 patches)
h8300: add missing L1_CACHE_SHIFT
mm: bugfix: set current->reclaim_state to NULL while returning from kswapd()
fanotify: fix missing break
revert "epoll: support for disabling items, and a self-test app"
checkpatch: improve network block comment style checking
Pull xfs bugfixes from Ben Myers:
- fix for large transactions spanning multiple iclog buffers
- zero the allocation_args structure on the stack before using it to
determine whether to use a worker for allocation
- move allocation stack switch to xfs_bmapi_allocate in order to
prevent deadlock on AGF buffers
- growfs no longer reads in garbage for new secondary superblocks
- silence a build warning
- ensure that invalid buffers never get written to disk while on free
list
- don't vmap inode cluster buffers during free
- fix buffer shutdown reference count mismatch
- fix reading of wrapped log data
* tag 'for-linus-v3.7-rc5' of git://oss.sgi.com/xfs/xfs:
xfs: fix reading of wrapped log data
xfs: fix buffer shudown reference count mismatch
xfs: don't vmap inode cluster buffers during free
xfs: invalidate allocbt blocks moved to the free list
xfs: silence uninitialised f.file warning.
xfs: growfs: don't read garbage for new secondary superblocks
xfs: move allocation stack switch up to xfs_bmapi_allocate
xfs: introduce XFS_BMAPI_STACK_SWITCH
xfs: zero allocation_args on the kernel stack
xfs: only update the last_sync_lsn when a transaction completes
Revert commit 03a7beb55b ("epoll: support for disabling items, and a
self-test app") pending resolution of the issues identified by Michael
Kerrisk, copied below.
We'll revisit this for 3.8.
: I've taken a look at this patch as it currently stands in 3.7-rc1, and
: done a bit of testing. (By the way, the test program
: tools/testing/selftests/epoll/test_epoll.c does not compile...)
:
: There are one or two places where the behavior seems a little strange,
: so I have a question or two at the end of this mail. But other than
: that, I want to check my understanding so that the interface can be
: correctly documented.
:
: Just to go though my understanding, the problem is the following
: scenario in a multithreaded application:
:
: 1. Multiple threads are performing epoll_wait() operations,
: and maintaining a user-space cache that contains information
: corresponding to each file descriptor being monitored by
: epoll_wait().
:
: 2. At some point, a thread wants to delete (EPOLL_CTL_DEL)
: a file descriptor from the epoll interest list, and
: delete the corresponding record from the user-space cache.
:
: 3. The problem with (2) is that some other thread may have
: previously done an epoll_wait() that retrieved information
: about the fd in question, and may be in the middle of using
: information in the cache that relates to that fd. Thus,
: there is a potential race.
:
: 4. The race can't solved purely in user space, because doing
: so would require applying a mutex across the epoll_wait()
: call, which would of course blow thread concurrency.
:
: Right?
:
: Your solution is the EPOLL_CTL_DISABLE operation. I want to
: confirm my understanding about how to use this flag, since
: the description that has accompanied the patches so far
: has been a bit sparse
:
: 0. In the scenario you're concerned about, deleting a file
: descriptor means (safely) doing the following:
: (a) Deleting the file descriptor from the epoll interest list
: using EPOLL_CTL_DEL
: (b) Deleting the corresponding record in the user-space cache
:
: 1. It's only meaningful to use this EPOLL_CTL_DISABLE in
: conjunction with EPOLLONESHOT.
:
: 2. Using EPOLL_CTL_DISABLE without using EPOLLONESHOT in
: conjunction is a logical error.
:
: 3. The correct way to code multithreaded applications using
: EPOLL_CTL_DISABLE and EPOLLONESHOT is as follows:
:
: a. All EPOLL_CTL_ADD and EPOLL_CTL_MOD operations should
: should EPOLLONESHOT.
:
: b. When a thread wants to delete a file descriptor, it
: should do the following:
:
: [1] Call epoll_ctl(EPOLL_CTL_DISABLE)
: [2] If the return status from epoll_ctl(EPOLL_CTL_DISABLE)
: was zero, then the file descriptor can be safely
: deleted by the thread that made this call.
: [3] If the epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY,
: then the descriptor is in use. In this case, the calling
: thread should set a flag in the user-space cache to
: indicate that the thread that is using the descriptor
: should perform the deletion operation.
:
: Is all of the above correct?
:
: The implementation depends on checking on whether
: (events & ~EP_PRIVATE_BITS) == 0
: This replies on the fact that EPOLL_CTL_AD and EPOLL_CTL_MOD always
: set EPOLLHUP and EPOLLERR in the 'events' mask, and EPOLLONESHOT
: causes those flags (as well as all others in ~EP_PRIVATE_BITS) to be
: cleared.
:
: A corollary to the previous paragraph is that using EPOLL_CTL_DISABLE
: is only useful in conjunction with EPOLLONESHOT. However, as things
: stand, one can use EPOLL_CTL_DISABLE on a file descriptor that does
: not have EPOLLONESHOT set in 'events' This results in the following
: (slightly surprising) behavior:
:
: (a) The first call to epoll_ctl(EPOLL_CTL_DISABLE) returns 0
: (the indicator that the file descriptor can be safely deleted).
: (b) The next call to epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY.
:
: This doesn't seem particularly useful, and in fact is probably an
: indication that the user made a logic error: they should only be using
: epoll_ctl(EPOLL_CTL_DISABLE) on a file descriptor for which
: EPOLLONESHOT was set in 'events'. If that is correct, then would it
: not make sense to return an error to user space for this case?
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Paton J. Lewis" <palewis@adobe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
