The addition of direct formatting of log items into the CIL
linear buffer added alignment restrictions that the start of each
vector needed to be 64 bit aligned. Hence padding was added in
xlog_finish_iovec() to round up the vector length to ensure the next
vector started with the correct alignment.
This adds a small number of bytes to the size of
the linear buffer that is otherwise unused. The issue is that we
then use the linear buffer size to determine the log space used by
the log item, and this includes the unused space. Hence when we
account for space used by the log item, it's more than is actually
written into the iclogs, and hence we slowly leak this space.
This results on log hangs when reserving space, with threads getting
stuck with these stack traces:
The 4 bytes is significant. Brain Foster did all the hard work in
tracking down a reproducable leak to inode chunk allocation (it went
away with the ikeep mount option). His rough numbers were that
creating 50,000 inodes leaked 11 log blocks. This turns out to be
roughly 800 inode chunks or 1600 inode cluster buffers. That
works out at roughly 4 bytes per cluster buffer logged, and at that
I started looking for a 4 byte leak in the buffer logging code.
What I found was that a struct xfs_buf_log_format structure for an
inode cluster buffer is 28 bytes in length. This gets rounded up to
32 bytes, but the vector length remains 28 bytes. Hence the CIL
ticket reservation is decremented by 32 bytes (via lv->lv_buf_len)
for that vector rather than 28 bytes which are written into the log.
The fix for this problem is to separately track the bytes used by
the log vectors in the item and use that instead of the buffer
length when accounting for the log space that will be used by the
formatted log item.
Again, thanks to Brian Foster for doing all the hard work and long
hours to isolate this leak and make finding the bug relatively
simple.
Signed-off-by: Dave Chinner <email address hidden>
Reviewed-by: Christoph Hellwig <email address hidden>
Reviewed-by: Brian Foster <email address hidden>
Signed-off-by: Dave Chinner <email address hidden>
Cc: Bill <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
This commit is a guesswork, but it seems to make sense to drop this
break, as otherwise the following line is never executed and becomes
dead code. And that following line actually saves the result of
local calculation by the pointer given in function argument. So the
proposed change makes sense if this code in the whole makes sense (but I
am unable to analyze it in the whole).
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=81641
Reported-by: David Binderman <email address hidden>
Signed-off-by: Andrey Utkin <email address hidden>
Signed-off-by: David S. Miller <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
The LDC handshake could have been asynchronously triggered
after ldc_bind() enables the ldc_rx() receive interrupt-handler
(and thus intercepts incoming control packets)
and before vio_port_up() calls ldc_connect(). If that is the case,
ldc_connect() should return 0 and let the state-machine
progress.
Signed-off-by: Sowmini Varadhan <email address hidden>
Acked-by: Karl Volz <email address hidden>
Signed-off-by: David S. Miller <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
Fix detection of BREAK on sunsab serial console: BREAK detection was only
performed when there were also serial characters received simultaneously.
To handle all BREAKs correctly, the check for BREAK and the corresponding
call to uart_handle_break() must also be done if count == 0, therefore
duplicate this code fragment and pull it out of the loop over the received
characters.
Patch applies to 3.16-rc6.
Signed-off-by: Christopher Alexander Tobias Schulze <email address hidden>
Signed-off-by: David S. Miller <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
Fix regression in bbc i2c temperature and fan control on some Sun systems
that causes the driver to refuse to load due to the bbc_i2c_bussel resource not
being present on the (second) i2c bus where the temperature sensors and fan
control are located. (The check for the number of resources was removed when
the driver was ported to a pure OF driver in mid 2008.)
Signed-off-by: Christopher Alexander Tobias Schulze <email address hidden>
Signed-off-by: David S. Miller <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
Based almost entirely upon a patch by Christopher Alexander Tobias
Schulze.
In commit db64fe02258f1507e13fe5212a989922323685ce ("mm: rewrite vmap
layer") lazy VMAP tlb flushing was added to the vmalloc layer. This
causes problems on sparc64.
Sparc64 has two VMAP mapped regions and they are not contiguous with
eachother. First we have the malloc mapping area, then another
unrelated region, then the vmalloc region.
This "another unrelated region" is where the firmware is mapped.
If the lazy TLB flushing logic in the vmalloc code triggers after
we've had both a module unload and a vfree or similar, it will pass an
address range that goes from somewhere inside the malloc region to
somewhere inside the vmalloc region, and thus covering the
openfirmware area entirely.
The sparc64 kernel learns about openfirmware's dynamic mappings in
this region early in the boot, and then services TLB misses in this
area. But openfirmware has some locked TLB entries which are not
mentioned in those dynamic mappings and we should thus not disturb
them.
These huge lazy TLB flush ranges causes those openfirmware locked TLB
entries to be removed, resulting in all kinds of problems including
hard hangs and crashes during reboot/reset.
Besides causing problems like this, such huge TLB flush ranges are
also incredibly inefficient. A plea has been made with the author of
the VMAP lazy TLB flushing code, but for now we'll put a safety guard
into our flush_tlb_kernel_range() implementation.
Since the implementation has become non-trivial, stop defining it as a
macro and instead make it a function in a C source file.
Signed-off-by: David S. Miller <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
The assumption was that update_mmu_cache() (and the equivalent for PMDs) would
only be called when the PTE being installed will be accessible by the user.
This is not true for code paths originating from remove_migration_pte().
There are dire consequences for placing a non-valid PTE into the TSB. The TLB
miss frramework assumes thatwhen a TSB entry matches we can just load it into
the TLB and return from the TLB miss trap.
So if a non-valid PTE is in there, we will deadlock taking the TLB miss over
and over, never satisfying the miss.
Just exit early from update_mmu_cache() and friends in this situation.
Based upon a report and patch from Christopher Alexander Tobias Schulze.
Signed-off-by: David S. Miller <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
This is a followup of commits f1d8cba61c3c4b ("inet: fix possible
seqlock deadlocks") and 7f88c6b23afbd315 ("ipv6: fix possible seqlock
deadlock in ip6_finish_output2")
Signed-off-by: Eric Dumazet <email address hidden>
Cc: Hannes Frederic Sowa <email address hidden>
Reported-by: Dave Jones <email address hidden>
Acked-by: Neil Horman <email address hidden>
Acked-by: Hannes Frederic Sowa <email address hidden>
Signed-off-by: David S. Miller <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
