From: Longlong Xia <xialonglong1@huawei.com> mainline inclusion from mainline-v6.2-rc7 commit 7717fc1a12f88701573f9ed897cc4f6699c661e3 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I645DG CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------- The softlockup still occurs in get_swap_pages() under memory pressure. 64 CPU cores, 64GB memory, and 28 zram devices, the disksize of each zram device is 50MB with same priority as si. Use the stress-ng tool to increase memory pressure, causing the system to oom frequently. The plist_for_each_entry_safe() loops in get_swap_pages() could reach tens of thousands of times to find available space (extreme case: cond_resched() is not called in scan_swap_map_slots()). Let's add cond_resched() into get_swap_pages() when failed to find available space to avoid softlockup. Link: https://lkml.kernel.org/r/20230128094757.1060525-1-xialonglong1@huawei.com Signed-off-by: Longlong Xia <xialonglong1@huawei.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Cc: Chen Wandun <chenwandun@huawei.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> --- mm/swapfile.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/swapfile.c b/mm/swapfile.c index eaf483c7c83e..9fe12f0b9205 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1104,6 +1104,7 @@ int get_swap_pages(int n_goal, swp_entry_t swp_entries[], int entry_size) goto check_out; pr_debug("scan_swap_map of si %d failed to find offset\n", si->type); + cond_resched(); spin_lock(&swap_avail_lock); nextsi: -- 2.25.1