While playing with fault injection, I hit this quite easily.
kernel BUG at fs/btrfs/extent_io.c:990!
invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
CPU: 1 PID: 1270 Comm: fsx Not tainted 3.16.0+ #41
task: ffff88023fe46d60 ti: ffff8802405a8000 task.ti: ffff8802405a8000
RIP: 0010:[<ffffffffc0319af4>] [<ffffffffc0319af4>]
__set_extent_bit+0x574/0x660 [btrfs]
...
[<ffffffff851be7fc>] ? set_track+0x9c/0x140
[<ffffffffc031aa94>] lock_extent_bits+0x94/0x310 [btrfs]
[<ffffffff85166454>] ? pagecache_get_page+0xb4/0x210
[<ffffffffc030d4de>] lock_and_cleanup_extent_if_need+0xee/0x1f0 [btrfs]
[<ffffffffc030e6e1>] __btrfs_buffered_write+0x1b1/0x680 [btrfs]
[<ffffffff850a258b>] ? preempt_count_sub+0xab/0x100
[<ffffffffc030ed2e>] btrfs_file_write_iter+0x17e/0x570 [btrfs]
[<ffffffff851d78ce>] new_sync_write+0x8e/0xd0
[<ffffffff851d8127>] vfs_write+0xb7/0x1f0
[<ffffffff851d8d68>] SyS_write+0x58/0xd0
[<ffffffff8576371f>] tracesys+0xdd/0xe2
989 prealloc = alloc_extent_state_atomic(prealloc);
990 BUG_ON(!prealloc);
541 static struct extent_state *
542 alloc_extent_state_atomic(struct extent_state *prealloc)
543 {
544 if (!prealloc)
545 prealloc = alloc_extent_state(GFP_ATOMIC);
546
547 return prealloc;
548 }
Going BUG() on a GFP_ATOMIC allocation failure seems a bit excessive.
Surely there's something better we can do here ?
Dave
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
