Deepa Dinamani 60f05dddf1 sock: Make sock->sk_stamp thread-safe ... [ Upstream commit 3a0ed3e961 ] Al Viro mentioned (Message-ID <20170626041334.GZ10672@ZenIV.linux.org.uk>) that there is probably a race condition lurking in accesses of sk_stamp on 32-bit machines. sock->sk_stamp is of type ktime_t which is always an s64. On a 32 bit architecture, we might run into situations of unsafe access as the access to the field becomes non atomic. Use seqlocks for synchronization. This allows us to avoid using spinlocks for readers as readers do not need mutual exclusion. Another approach to solve this is to require sk_lock for all modifications of the timestamps. The current approach allows for timestamps to have their own lock: sk_stamp_lock. This allows for the patch to not compete with already existing critical sections, and side effects are limited to the paths in the patch. The addition of the new field maintains the data locality optimizations from commit 9115e8cd2a ("net: reorganize struct sock for better data locality") Note that all the instances of the sk_stamp accesses are either through the ioctl or the syscall recvmsg. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2019-01-09 17:38:33 +01:00
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acpi
asm-generic	mm: introduce mm_[p4d|pud|pmd]_folded	2018-12-29 13:37:58 +01:00
clocksource
crypto	crypto: speck - remove Speck	2018-11-13 11:08:46 -08:00
drm	drm: Get ref on CRTC commit object when waiting for flip_done	2018-10-18 14:23:13 -04:00
dt-bindings	ARM: SoC: late updates	2018-08-25 14:12:36 -07:00
keys
kvm
linux	ptr_ring: wrap back ->producer in __ptr_ring_swap_queue()	2019-01-09 17:38:33 +01:00
math-emu
media	media: cec: fix the Signal Free Time calculation	2018-11-13 11:08:53 -08:00
memory
misc
net	sock: Make sock->sk_stamp thread-safe	2019-01-09 17:38:33 +01:00
pcmcia	pcmcia: remove long deprecated pcmcia_request_exclusive_irq() function	2018-08-18 12:30:42 -07:00
ras
rdma	IB/rxe: Revise the ib_wr_opcode enum	2018-11-13 11:08:43 -08:00
scsi
soc	soc: fsl: qbman: add APIs to retrieve the probing status	2018-09-27 15:43:35 -05:00
sound	ALSA: pcm: Fix interval evaluation with openmin/max	2018-12-13 09:16:16 +01:00
target
trace	sched, trace: Fix prev_state output in sched_switch tracepoint	2018-12-08 12:59:06 +01:00
uapi	x86/speculation: Add prctl() control for indirect branch speculation	2018-12-05 19:32:04 +01:00
video	fbdev changes for v4.19:	2018-08-23 15:44:58 -07:00
xen	Revert "xen/balloon: Mark unallocated host memory as UNUSABLE"	2018-12-17 09:24:39 +01:00