Date: Sun, 18 Jun 2017 15:47:46 +0800 From: Jia-Ju Bai <baijiaju1990@163.com> To: Kevin Oberman <rkoberman@gmail.com> Cc: freebsd-drivers@freebsd.org, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Re: [Bug 220032] [if_alc] sys/dev/alc/if_alc.c: sleep-under-mutex bugs Message-ID: <fbc0f04f-b7cf-ee86-9681-d6dd97122038@163.com> In-Reply-To: <CAN6yY1uQxR3HTLYzy3uOwpcbLFGAKtCBxRU1HPAb8jjGVC9Hkg@mail.gmail.com> References: <7cc5abf5-f90c-c554-e54e-6f9534ef22ef@163.com> <CAN6yY1uQxR3HTLYzy3uOwpcbLFGAKtCBxRU1HPAb8jjGVC9Hkg@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Thanks a lot, your advice is very helpful :) I will submit a patch according to your advice, and update my bug report. By the way, I have found many similar possible bugs in network drivers in FreeBSD. And they are all caused by "BUS_DMA_WAITOK" in bus_dmamap_load and other dmamap-load related functions. If my reported bugs can be quickly confirmed, I will write and submit patches for them as soon as possible. I am looking forward to helpful comments and advice :) Thanks, Jia-Ju Bai On 2017/6/18 13:31, Kevin Oberman wrote: > On Fri, Jun 16, 2017 at 2:03 AM, Jia-Ju Bai <baijiaju1990@163.com > <mailto:baijiaju1990@163.com>> wrote: > > The alc driver may sleep under a mutex, and the function call > paths in file > "sys/dev/alc/if_alc.c" in FreeBSD 11.0 is: > alc_resume [line 2648: acquire the mutex] > alc_init_locked [line 2664] > alc_init_rx_ring [line 3911] > alc_newbuf [line 4469] > bus_dmamap_load_mbuf_sg(BUS_DMA_WAITOK) [line 3472] --> > may sleep > > alc_int_task [line 3330: acquire the mutex] > alc_start_locked [line 3372] > alc_encap [line 2942] > bus_dmamap_load_mbuf_sg(BUS_DMA_WAITOK) [line 2780] --> may > sleep > > The possible fix of these bugs is to set the last parameter in > bus_dmamap_load_mbuf_sg to "BUS_DMA_NOWAIT". > > This bug is found by a static analysis tool written by myself, and > it is > checked by my review of the FreeBSD code. > > By the way, I am a freshman in developing FreeBSD drivers, and I > am willing to > submit a patch. But I do not know how to write and submit a patch, > and where to > submit, so I am looking forward to useful advice :) > > Jia-Ju Bai > > > To submit a patch, use svn to download the source from a repository. > Be sure the file in your source directory is the current, unmodified file. > Edit the file or files as needed to correct the bug > Generate the diff with the command "svn diff > path-to-directory-containing-file(s) > diff-file.diff" > Update the bug report attaching the patch (with a brief description) > -- > Kevin Oberman, Part time kid herder and retired Network Engineer > E-mail: rkoberman@gmail.com <mailto:rkoberman@gmail.com> > PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?fbc0f04f-b7cf-ee86-9681-d6dd97122038>