mm/memory.c: release locked page in do_swap_page()
authorMinchan Kim <minchan@kernel.org>
Fri, 19 Jan 2018 00:33:50 +0000 (16:33 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 19 Jan 2018 18:09:40 +0000 (10:09 -0800)
commitf80207727aaca3aa34a9cd80659393534de69cad
treed9dc20d2ea690f091761bf6f5eed8d474f1f4857
parentdda3e15231b35840fe6f0973f803cc70ddb86281
mm/memory.c: release locked page in do_swap_page()

James reported a bug in swap paging-in from his testing.  It is that
do_swap_page doesn't release locked page so system hang-up happens due
to a deadlock on PG_locked.

It was introduced by 0bcac06f27d7 ("mm, swap: skip swapcache for swapin
of synchronous device") because I missed swap cache hit places to update
swapcache variable to work well with other logics against swapcache in
do_swap_page.

This patch fixes it.

Debugged by James Bottomley.

Link: http://lkml.kernel.org/r/<1514407817.4169.4.camel@HansenPartnership.com>
Link: http://lkml.kernel.org/r/20180102235606.GA19438@bbox
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: James Bottomley <James.Bottomley@hansenpartnership.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/memory.c