Hi Warner, Sorry, I need to make a correction: acutally it looks the panic can NOT reproduce with stable/11 or the latest master branch. This is great! :-)
Actually I was using an old version of the master branch that doesn’t have r328554 yet, and I could 100% reproduce the issue. If I manually apply r328554, or I use the latest master branch, the panic can’t happen any more. So, it looks here we don’t need to MFC any patch to stable/11. Thanks, -- Dexuan From: wl...@bsdimp.com <wl...@bsdimp.com> On Behalf Of Warner Losh Sent: Monday, March 12, 2018 09:45 To: Dexuan-BSD Cui <dexuan....@gmail.com> Cc: Warner Losh <i...@freebsd.org>; src-committers <src-committ...@freebsd.org>; svn-src-...@freebsd.org; svn-src-head@freebsd.org; Dexuan Cui <de...@microsoft.com> Subject: Re: svn commit: r328554 - head/sys/cam/scsi This sender failed our fraud detection checks and may not be who they appear to be. Learn about spoofing<http://aka.ms/LearnAboutSpoofing> Feedback<http://aka.ms/SafetyTipsFeedback> I think this is a good idea to MFC. We've had no reports of it causing issues. There's more extensive locking changes / tweaks needed for da that just went in that likely should also be MFC'd. Warner On Sun, Mar 11, 2018 at 9:17 PM, Dexuan-BSD Cui <dexuan....@gmail.com<mailto:dexuan....@gmail.com>> wrote: Hi imp and all, I think this patch is very important, because it can fix a panic I noticed recently when I try to hot-remove a SCSI disk from a VM running on Azure/Hyper-V. The panic is almost 100% reproducible with stable/11, but not in the latest CURRENT code, so finally I identified this fix in the CURRENT branch. Can you please MFC this patch to 11 and 10? It looks there is a major difference in the CAM code between 11/10 and the CURRENT code, and we may have to MFC more related patches. If this is difficult, I hope at least we can provide a minimal re-written version of the patch to 11 and 10? Looking forward to your insight! Thanks, -- Dexuan On Mon, Jan 29, 2018 at 10:07 AM, Warner Losh <i...@freebsd.org<mailto:i...@freebsd.org>> wrote: > Author: imp > Date: Mon Jan 29 18:07:14 2018 > New Revision: 328554 > URL: > https://svnweb.freebsd.org/changeset/base/328554<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsvnweb.freebsd.org%2Fchangeset%2Fbase%2F328554&data=04%7C01%7Cdecui%40microsoft.com%7Ce4d8e3802c8c48bf969808d58838904f%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636564698908750058%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwifQ%3D%3D%7C100&sdata=SuKthNA5u96YZYfGmFTKTkCHI%2F5nIje9uWdphapANlY%3D&reserved=0> > > Log: > Do the book-keeping on release before we release the reference. The > periph was going away on final release, and then returning and we > started dancing in free memory. > > Sponsored by: Netflix > > Modified: > head/sys/cam/scsi/scsi_da.c > > Modified: head/sys/cam/scsi/scsi_da.c > ============================================================================== > --- head/sys/cam/scsi/scsi_da.c Mon Jan 29 17:32:30 2018 (r328553) > +++ head/sys/cam/scsi/scsi_da.c Mon Jan 29 18:07:14 2018 (r328554) > @@ -1549,12 +1549,12 @@ da_periph_unhold(struct cam_periph *periph, da_ref_tok > struct da_softc *softc = periph->softc; > > token_sanity(token); > - cam_periph_unhold(periph); > DA_PERIPH_PRINT(periph, "Unholding device %s (%d)\n", > da_ref_text[token], token); > cnt = atomic_fetchadd_int(&softc->ref_flags[token], -1); > if (cnt != 1) > panic("Unholding %d with cnt = %d", token, cnt); > + cam_periph_unhold(periph); > } > > static inline int > @@ -1583,12 +1583,12 @@ da_periph_release(struct cam_periph *periph, da_ref_to > struct da_softc *softc = periph->softc; > > token_sanity(token); > - cam_periph_release(periph); > DA_PERIPH_PRINT(periph, "releasing device %s (%d)\n", > da_ref_text[token], token); > cnt = atomic_fetchadd_int(&softc->ref_flags[token], -1); > if (cnt != 1) > panic("Releasing %d with cnt = %d", token, cnt); > + cam_periph_release(periph); > } > > static inline void > @@ -1598,12 +1598,12 @@ da_periph_release_locked(struct cam_periph *periph, da > struct da_softc *softc = periph->softc; > > token_sanity(token); > - cam_periph_release_locked(periph); > DA_PERIPH_PRINT(periph, "releasing device (locked) %s (%d)\n", > da_ref_text[token], token); > cnt = atomic_fetchadd_int(&softc->ref_flags[token], -1); > if (cnt != 1) > panic("Unholding %d with cnt = %d", token, cnt); > + cam_periph_release_locked(periph); > } > > #define cam_periph_hold POISON > _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
