From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: NeilBrown To: Francesco Dolcini Date: Fri, 07 Oct 2016 13:09:11 +1100 Cc: Francesco Dolcini , axboe@kernel.dk, tj@kernel.org, hch@lst.de, axboe@fb.com, akpm@linux-foundation.org, linux-block@vger.kernel.org Subject: Re: blockdev kernel regression (bugzilla 173031) In-Reply-To: <20161006075409.GA4059@dev1> References: <20161004150350.GA27176@dev1> <8760p75zc6.fsf@notabene.neil.brown.name> <20161005111826.GA2430@dev1> <87k2dm3ueb.fsf@notabene.neil.brown.name> <20161006075409.GA4059@dev1> Message-ID: <8760p452rc.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" List-ID: --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Thu, Oct 06 2016, Francesco Dolcini wrote: > On Thu, Oct 06, 2016 at 04:42:52PM +1100, NeilBrown wrote: > cc >> Maybe there is a race, but that seems unlikely. > > Consider that just hot removal while writing is not enough to=20 > reproduce systematically the bug. > > while true; do [ ! -f /media/usb/.not_mounted ] \ > && dd if=3D/dev/zero of=3D/media/usb/aaa bs=3D1k \ > count=3D1 2>/dev/null && echo -n '*' ; done > > with lazy umount by mdev on USB flash drive removal > > reproduce the problem pretty always > >> The vfat issue is different, and is only a warning. > Why you say is only a warning? Here the Oops with vfat on ARM/i.MX6: I looked at: x86 Oops information (with vfat): in the bugzilla and didn't realized there was another one further down. That first vfat on is just a warning. > >> > Regression is on commit 6cd18e7 ("block: destroy bdi before blockdev i= s unregistered.") >> > >> > Commit: bdfe0cbd746a ("Revert "ext4: remove block_device_ejected") is = already present on 4.1 stable I am currently working on (2a6f417 on 4.1 bra= nch) >> > >> > I wonder if commit b02176f ("block: don't release bdi while request_qu= eue has live references") is the correct fix for this also in kernel 4.1. >>=20 >> Maybe. It is worth a try. >>=20 >> Below is a a backport to 4.1.33. It compiles, but I haven't tested. >> If it works for you, I can recommend it for -stable. > > I confirm that it works! Thanks. NeilBrown --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIcBAEBCAAGBQJX9wPHAAoJEDnsnt1WYoG5IuYP/AuiWH0uuGzpXjnwtm5YcqrO XOj+LzJfAnkmuKLJZRM6kR2KwBSeTIaV9JebzsL1ybrPOIxUPmszv3fAnA4v3sX9 swBr2+XR5MnEzfYI0bKju7nZ6kQGZWRRa2u8LzyBvl9/I5U6sGzlD4/yicgi1zWh 6AHBnwN0rn6HtbhQs2SSah3Ef2e+CJAlU/iKW1MCFYKskaCNlUY7IkiBOGMnVS48 jZPURL0Q6iG/kUB9YN/rhZG3eHUIKwT6AaOG1F0GA3I7WDWQ13f8kyo/WuwuSpV/ FD12xBh9ZAma2WJSnUVcJkBpXFJYXxs7otomLZwsvWdhZrgaLtvdjCVoCDRmvVBn zKcQ7+aYjnvu9s30PS4NINuHyvGxCfcPTNfEwOxg09oMC/WjgXZEE3dM1Sc3v2Jl vO59ZnBnDM0q+cKCOu5Ioef10sOksp1oGp+FV++MhQDBfQs4Yk9XpSVgEIrrOux4 KCqjyOestz654R2drVDjUgX2+7g/+77XoDe4F1KEAHzFWIUUg4rraxHOtqZejZM8 ElHMzipQNPuYZthvt+1kAgeWx1nfED4JAxkUX3X2khK/qivWpeL7Fa+BDYIbC++m y2XXeGv5km1wRgnx4RdsHj7dIQxfETALiYyWDlpLhEDqjIocFW7vXW3BloPQs4Xt eYtR+BJWKMQdlHl2nIPU =PeJw -----END PGP SIGNATURE----- --=-=-=--