On Tue, Feb 20, 2018 at 08:44:57PM +0800, Anand Jain wrote: > > > On 02/20/2018 07:40 PM, Nikolay Borisov wrote: > > Patch 11ac3f1da5fd ("btrfs: log, when replace, is canceled by the user") > > added a new btrfs_info call with a couple of btrfs_dev_name() args. This > > is wrong since the latter require being called in rcu read side > > critical section. Fix it by instead calling btrfs_info_in_rcu. This > > fixes the following splat: > > > > ============================= > > WARNING: suspicious RCU usage > > 4.16.0-rc2-nbor #463 Not tainted > > ----------------------------- > > fs/btrfs/dev-replace.c:318 suspicious rcu_dereference_check() usage! > > > > other info that might help us debug this: > > > > rcu_scheduler_active = 2, debug_locks = 1 > > 1 lock held by btrfs/5698: > > #0: (&fs_info->dev_replace.lock_finishing_cancel_unmount){+.+.}, at: > > [<00000000942cb4ee>] btrfs_dev_replace_cancel+0xac/0x3f0 > > > > stack backtrace: > > CPU: 2 PID: 5698 Comm: btrfs Not tainted 4.16.0-rc2-nbor #463 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > > Ubuntu-1.8.2-1ubuntu1 04/01/2014 > > Call Trace: > > dump_stack+0x85/0xc9 > > lockdep_rcu_suspicious+0x123/0x170 > > btrfs_dev_name.part.1+0x6d/0x80 > > btrfs_dev_replace_cancel+0x330/0x3f0 > > btrfs_ioctl+0x2751/0x65b0 > > ? debug_check_no_locks_freed+0x290/0x290 > > ? trace_hardirqs_on_caller+0x400/0x570 > > ? trace_hardirqs_on+0xd/0x10 > > ? btrfs_ioctl_get_supported_features+0x30/0x30 > > ? __handle_mm_fault+0x1aca/0x3230 > > ? lock_downgrade+0x650/0x650 > > ? trace_hardirqs_on+0xd/0x10 > > ? mem_cgroup_commit_charge+0xc0/0xdd0 > > ? _raw_spin_unlock+0x27/0x40 > > ? __handle_mm_fault+0x1aca/0x3230 > > ? lock_downgrade+0x650/0x650 > > ? vm_insert_page+0x650/0x650 > > ? __vma_link_rb+0x125/0x1d0 > > do_vfs_ioctl+0x184/0xf00 > > ? do_vfs_ioctl+0x184/0xf00 > > ? lock_downgrade+0x650/0x650 > > ? ioctl_preallocate+0x1a0/0x1a0 > > ? up_read+0x1f/0x40 > > ? __do_page_fault+0x5c6/0xb30 > > ? SyS_brk+0x412/0x5f0 > > ? mm_fault_error+0x2e0/0x2e0 > > SyS_ioctl+0x41/0x70 > > ? do_vfs_ioctl+0xf00/0xf00 > > do_syscall_64+0x19d/0x5d0 > > entry_SYSCALL_64_after_hwframe+0x42/0xb7 > > > > Fixes: 11ac3f1da5fd ("btrfs: log, when replace, is canceled by the user") > > Signed-off-by: Nikolay Borisov <nbori...@suse.com> > > I notice too. Thanks Nikolay for the fix.
I'll fold the fix into the original patch. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html