Kan Liang 1ee1c3f5b5 mm: allow page_cache_get_speculative in interrupt context ... Kernel panic when calling the IRQ-safe __get_user_pages_fast in NMI handler. The bug was introduced by commit 2947ba054a ("x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation"). The original x86 __get_user_page_fast used plain get_page() or page_ref_add(). However, the generic __get_user_page_fast uses page_cache_get_speculative(), which has VM_BUG_ON(in_interrupt()). There is no reason to prevent page_cache_get_speculative from using in interrupt context. According to the author, putting a BUG_ON there is just because the code is not verifying correctness of interrupt races. I did some tests in interrupt context. There is no issue found. Removing VM_BUG_ON(in_interrupt()) for page_cache_get_speculative(). Link: http://lkml.kernel.org/r/1501609146-59730-1-git-send-email-kan.liang@intel.com Fixes: 2947ba054a ("x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation") Signed-off-by: Kan Liang <kan.liang@intel.com> Cc: Jens Axboe <axboe@fb.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Ying Huang <ying.huang@intel.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2017-08-02 17:16:13 -07:00
..
acpi	ACPI: NUMA: add missing include in acpi_numa.h	2017-07-24 22:27:43 +02:00
asm-generic	Merge branch 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2017-07-15 11:17:52 -07:00
clocksource	…
crypto	…
drm	i915, amd and some core fixes + mediatek color support	2017-07-13 11:26:18 -07:00
dt-bindings	Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus	2017-07-15 10:59:54 -07:00
keys	…
kvm	…
linux	mm: allow page_cache_get_speculative in interrupt context	2017-08-02 17:16:13 -07:00
math-emu	…
media	…
memory	…
misc	…
net	udp6: fix socket leak on early demux	2017-07-29 14:19:03 -07:00
pcmcia	…
ras	…
rdma	IB/cma: Fix reference count leak when no ipv4 addresses are set	2017-07-20 11:24:13 -04:00
rxrpc	…
scsi	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2017-07-13 14:27:32 -07:00
soc	…
sound	…
target	iscsi-target: Add login_keys_workaround attribute for non RFC initiators	2017-07-11 10:56:39 -07:00
trace	mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic	2017-07-12 16:26:03 -07:00
uapi	TTY/Serial fixes for 4.13-rc2	2017-07-22 09:00:24 -07:00
video	…
xen	xen/balloon: don't online new memory initially	2017-07-23 08:13:18 +02:00