The patch titled
mm: swapfile, fix crash on double swapon
has been added to the -mm tree. Its filename is
swap_info-include-first_swap_extent-fix.patch
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------------------------------------------------------
Subject: mm: swapfile, fix crash on double swapon
From: Jiri Slaby <jirislaby@xxxxxxxxx>
Double swapon on a device causes a crash:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff810af160>] sys_swapon+0x1f0/0xc60
PGD 1dc0b067 PUD 1dc09067 PMD 0
Oops: 0000 [#1] SMP
last sysfs file:
CPU 1
Modules linked in:
Pid: 562, comm: swapon Tainted: G W 2.6.32-rc5-mm1_64 #867
RIP: 0010:[<ffffffff810af160>] [<ffffffff810af160>] sys_swapon+0x1f0/0xc60
...
It is due to swap_info_struct->first_swap_extent.list not being
initialized. ->next is NULL in such a situation and
destroy_swap_extents fails to iterate over the list with the BUG
above.
Introduced by swap_info-include-first_swap_extent.patch. Revert the
INIT_LIST_HEAD move.
Signed-off-by: Jiri Slaby <jirislaby@xxxxxxxxx>
Acked-by: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN mm/swapfile.c~swap_info-include-first_swap_extent-fix mm/swapfile.c
--- a/mm/swapfile.c~swap_info-include-first_swap_extent-fix
+++ a/mm/swapfile.c
@@ -1365,7 +1365,6 @@ add_swap_extent(struct swap_info_struct
if (start_page == 0) {
se = &sis->first_swap_extent;
sis->curr_swap_extent = se;
- INIT_LIST_HEAD(&se->list);
se->start_page = 0;
se->nr_pages = nr_pages;
se->start_block = start_block;
@@ -1818,6 +1817,7 @@ SYSCALL_DEFINE2(swapon, const char __use
kfree(p);
goto out;
}
+ INIT_LIST_HEAD(&p->first_swap_extent.list);
if (type >= nr_swapfiles) {
p->type = type;
swap_info[type] = p;
_
Patches currently in -mm which might be from jirislaby@xxxxxxxxx are
origin.patch
linux-next.patch
isdn-hisax-fix-lock-imbalance.patch
isdn-eicon-use-offsetof.patch
isdn-eicon-return-on-error.patch
swap_info-include-first_swap_extent-fix.patch
cyclades-allow-overriding-isa-defaults-also-when-the-driver-is-built-in.patch
char-mxser-remove-unnecessary-tty-test.patch
isicomc-use-pr_fmt-and-pr_level.patch
reiser4.patch
fs-reiser4-add-parenths-around-x-y.patch
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