On 12/5/18 5:19 AM, Kirill Tkhai wrote: > Hi, > > commit 529262d56dbe from today linux-next makes my kernel crash: > > Author: Christoph Hellwig <hch@xxxxxx> > Date: Sun Dec 2 17:46:26 2018 +0100 > > block: remove ->poll_fn > > Traceback is below, config and reproducer (not minimal, just a random one populating swap) are attached. > > [ 29.097612] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 > [ 29.098730] #PF error: [INSTR] > [ 29.099104] PGD 0 P4D 0 > [ 29.099425] Oops: 0010 [#1] PREEMPT SMP > [ 29.099879] CPU: 3 PID: 925 Comm: bash Not tainted 4.20.0-rc5-next-20181205+ #244 > [ 29.100658] RIP: 0010: (null) > [ 29.101100] Code: Bad RIP value. > [ 29.101480] RSP: 0000:ffffc9000023fb80 EFLAGS: 00010202 > [ 29.102061] RAX: ffffffff8182d0e0 RBX: ffff88807ceee000 RCX: 0000000000000000 > [ 29.102818] RDX: ffff88807d560f40 RSI: 0000000000000000 RDI: ffff88807ceee000 > [ 29.103661] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000002000 > [ 29.104560] R10: 00000000ffffffff R11: ffff88807c854150 R12: 0000000000000000 > [ 29.105458] R13: 0000000000000002 R14: ffff88807d7236c0 R15: ffffc9000023fe20 > [ 29.106438] FS: 00007faba91d7740(0000) GS:ffff88807db80000(0000) knlGS:0000000000000000 > [ 29.107304] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 29.107917] CR2: ffffffffffffffd6 CR3: 000000007a172000 CR4: 00000000000006a0 > [ 29.109401] Call Trace: > [ 29.110017] ? blk_poll+0x27c/0x340 > [ 29.110691] ? submit_bio+0x40/0x120 > [ 29.111278] ? swap_readpage+0x148/0x190 > [ 29.111924] ? read_swap_cache_async+0x53/0x60 > [ 29.112670] ? swap_cluster_readahead+0x231/0x2b0 > [ 29.113310] ? swapin_readahead+0x2ce/0x400 > [ 29.113878] ? pagecache_get_page+0x2b/0x210 > [ 29.114416] ? do_swap_page+0x42c/0x800 > [ 29.114919] ? __handle_mm_fault+0x544/0xdd0 > [ 29.115455] ? handle_mm_fault+0x112/0x230 > [ 29.115978] ? __do_page_fault+0x196/0x410 > [ 29.116501] ? __put_user_4+0x19/0x20 > [ 29.116990] ? page_fault+0x5/0x20 > [ 29.117451] ? page_fault+0x1b/0x20 > [ 29.117925] CR2: 0000000000000000 > [ 29.118472] ---[ end trace 0faa4ddc190b41fa ]--- Can you try this? The swap read-in poll attempts looks totally incorrect. diff --git a/mm/page_io.c b/mm/page_io.c index 5bdfd21c1bd9..f3455f9f8dc7 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -401,6 +401,8 @@ int swap_readpage(struct page *page, bool synchronous) get_task_struct(current); bio->bi_private = current; bio_set_op_attrs(bio, REQ_OP_READ, 0); + if (synchronous) + bio->bi_opf |= REQ_HIPRI; count_vm_event(PSWPIN); bio_get(bio); qc = submit_bio(bio); @@ -411,7 +413,7 @@ int swap_readpage(struct page *page, bool synchronous) break; if (!blk_poll(disk->queue, qc, true)) - break; + io_schedule(); } __set_current_state(TASK_RUNNING); bio_put(bio); -- Jens Axboe
