On 12/5/18 6:05 AM, Kirill Tkhai wrote: > On 05.12.2018 15:45, Jens Axboe wrote: >> 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); > > Still crashes: What device is this? -- Jens Axboe
