• Minchan Kim's avatar
    mm: call swap_slot_free_notify() with page lock held · b06bad17
    Minchan Kim authored
    Kyeongdon reported below error which is BUG_ON(!PageSwapCache(page)) in
    page_swap_info.  The reason is that page_endio in rw_page unlocks the
    page if read I/O is completed so we need to hold a PG_lock again to
    check PageSwapCache.  Otherwise, the page can be removed from swapcache.
    
      Kernel BUG at c00f9040 [verbose debug info unavailable]
      Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
      Modules linked in:
      CPU: 4 PID: 13446 Comm: RenderThread Tainted: G        W 3.10.84-g9f14aec-dirty #73
      task: c3b73200 ti: dd192000 task.ti: dd192000
      PC is at page_swap_info+0x10/0x2c
      LR is at swap_slot_free_notify+0x18/0x6c
      pc : [<c00f9040>]    lr : [<c00f5560>]    psr: 400f0113
      sp : dd193d78  ip : c2deb1e4  fp : da015180
      r10: 00000000  r9 : 000200da  r8 : c120fe08
      r7 : 00000000  r6 : 00000000  r5 : c249a6c0  r4 : = c249a6c0
      r3 : 00000000  r2 : 40080009  r1 : 200f0113  r0 : = c249a6c0
      ..<snip> ..
      Call Trace:
        page_swap_info+0x10/0x2c
        swap_slot_free_notify+0x18/0x6c
        swap_readpage+0x90/0x11c
        read_swap_cache_async+0x134/0x1ac
        swapin_readahead+0x70/0xb0
        handle_pte_fault+0x320/0x6fc
        handle_mm_fault+0xc0/0xf0
        do_page_fault+0x11c/0x36c
        do_DataAbort+0x34/0x118
    
    Fixes: 3f2b1a04 ("zram: revive swap_slot_free_notify")
    Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
    Tested-by: default avatarKyeongdon Kim <kyeongdon.kim@lge.com>
    Cc: Hugh Dickins <hughd@google.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    b06bad17
page_io.c 9.28 KB