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authorMinchan Kim <minchan@kernel.org>2018-01-18 16:33:50 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-01-19 10:09:40 -0800
commitf80207727aaca3aa34a9cd80659393534de69cad (patch)
treed9dc20d2ea690f091761bf6f5eed8d474f1f4857
parentdda3e15231b35840fe6f0973f803cc70ddb86281 (diff)
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>
-rw-r--r--mm/memory.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/mm/memory.c b/mm/memory.c
index ca5674cbaff2..793004608332 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2857,8 +2857,11 @@ int do_swap_page(struct vm_fault *vmf)
int ret = 0;
bool vma_readahead = swap_use_vma_readahead();
- if (vma_readahead)
+ if (vma_readahead) {
page = swap_readahead_detect(vmf, &swap_ra);
+ swapcache = page;
+ }
+
if (!pte_unmap_same(vma->vm_mm, vmf->pmd, vmf->pte, vmf->orig_pte)) {
if (page)
put_page(page);
@@ -2889,9 +2892,12 @@ int do_swap_page(struct vm_fault *vmf)
delayacct_set_flag(DELAYACCT_PF_SWAPIN);
- if (!page)
+ if (!page) {
page = lookup_swap_cache(entry, vma_readahead ? vma : NULL,
vmf->address);
+ swapcache = page;
+ }
+
if (!page) {
struct swap_info_struct *si = swp_swap_info(entry);