Date: Mon, 20 Jan 2025 20:48:47 +0800 From: Zhenlei Huang <zlei@FreeBSD.org> To: Warner Losh <imp@bsdimp.com> Cc: Warner Losh <imp@freebsd.org>, FreeBSD Stable ML <stable@freebsd.org>, Edward Tomasz Napierala <trasz@freebsd.org> Subject: Re: MFC fixes for uninitialized kernel stack variables in sys/cam or do direct fix for pvscsi driver Message-ID: <56C24758-E34A-4A68-9E1D-8F7D27ADD0DF@FreeBSD.org> In-Reply-To: <CANCZdfqCy=TdPRGrTKj=7DJz9nSyPFZgBnsPuf4FqgurN4oYiw@mail.gmail.com> References: <0DDE1B66-B794-472D-A901-54FA2FF1E853@FreeBSD.org> <CANCZdfpKGMFyPAVqxPcahZXgSL=tFBin3ratjoQTtJrDeM2NUg@mail.gmail.com> <3CB8230B-7938-4503-AADD-7F691482908C@FreeBSD.org> <E39D3960-42CE-4290-AF31-EA385D8512AF@FreeBSD.org> <C12BB5CB-ED16-4856-ADE1-6D788FB9799E@FreeBSD.org> <CANCZdfqCy=TdPRGrTKj=7DJz9nSyPFZgBnsPuf4FqgurN4oYiw@mail.gmail.com>
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--Apple-Mail=_C93059E6-FA1F-4D0E-866B-7EA4A7E58A8D Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Jan 15, 2025, at 12:37 PM, Warner Losh <imp@bsdimp.com> wrote: >=20 > Great. This looks good. MFSing is done, along with the following commits those clear the stack = allocated CCBs. 076686fe0703 cam: make sure to clear CCBs allocated on the stack ec5325dbca62 cam: make sure to clear even more CCBs allocated on the = stack 0f206cc91279 cam: add missing zeroing of a stack-allocated CCB. 616a676a0535 cam: clear stack-allocated CCB in the target layer Everything looks good so far. Best regards, Zhenlei >=20 > Warner >=20 > On Tue, Jan 14, 2025, 9:36=E2=80=AFPM Zhenlei Huang <zlei@freebsd.org = <mailto:zlei@freebsd.org>> wrote: >=20 >=20 >> On Jan 13, 2025, at 5:06 PM, Zhenlei Huang <zlei@FreeBSD.org = <mailto:zlei@FreeBSD.org>> wrote: >>=20 >>=20 >>=20 >>> On Jan 13, 2025, at 4:22 PM, Zhenlei Huang <zlei@FreeBSD.org = <mailto:zlei@FreeBSD.org>> wrote: >>>=20 >>>=20 >>>=20 >>>> On Dec 28, 2024, at 6:03 AM, Warner Losh <imp@bsdimp.com = <mailto:imp@bsdimp.com>> wrote: >>>>=20 >>>>=20 >>>>=20 >>>> On Mon, Dec 2, 2024 at 2:41=E2=80=AFAM Zhenlei Huang = <zlei@freebsd.org <mailto:zlei@freebsd.org>> wrote: >>>> Hi Warner, >>>>=20 >>>> Recently I upgraded some ESXi vms from 13.3 to 13.4 and noticed = weird report for sas speed. >>>> The boot console has the following, >>>>=20 >>>> ``` >>>> da0 at pvscsi0 bus 0 scbus2 target 0 lun 0 >>>> da0: <VMware Virtual disk 2.0> Fixed Direct Access SPC-4 SCSI = device >>>> da0: 4294967.295MB/s transfers >>>> ``` >>>> But camcontrol report the correct value, >>>> ``` >>>> # camcontrol inquiry da0 -R >>>> pass1: 750.000MB/s transfers, Command Queueing Enabled >>>> ``` >>>>=20 >>>> The `4294967.295MB` is actually 0xffff_ffff or -1 but I do not see = any logic set those values. >>>>=20 >>>> Finally I managed to get the stack trace, >>>> ``` >>>> _scsi_announce_periph >>>> scsi_announce_periph_sbuf >>>> xpt_announce_periph_sbuf >>>> dadone_proberc >>>> xpt_done_process >>>> xpt_done_td >>>> fork_exit >>>> fork_trampoline >>>> ``` >>>>=20 >>>> and noticed that the last param `cts` of = `_scsi_announce_periph(struct cam_periph *periph, u_int *speed, u_int = *freq, struct ccb_trans_settings *cts)` >>>> is from kernel stack and is not properly initialized, latter I = found some commits related to this, >>>>=20 >>>> 076686fe0703 cam: make sure to clear CCBs allocated on the stack >>>> ec5325dbca62 cam: make sure to clear even more CCBs allocated on = the stack >>>> 0f206cc91279 cam: add missing zeroing of a stack-allocated CCB. >>>> 616a676a0535 cam: clear stack-allocated CCB in the target layer >>>>=20 >>>> I applied them to stable/13, rebuild and reboot, now the speed of = da0 is reported correctly. I also tried to patch the pvscsi driver with = few lines and >>>> it also works as intended. >>>>=20 >>>> ``` >>>> --- a/sys/dev/vmware/pvscsi/pvscsi.c >>>> +++ b/sys/dev/vmware/pvscsi/pvscsi.c >>>> @@ -1444,6 +1444,10 @@ pvscsi_action(struct cam_sim *sim, union ccb = *ccb) >>>> cts->proto_specific.scsi.flags =3D = CTS_SCSI_FLAGS_TAG_ENB; >>>> cts->proto_specific.scsi.valid =3D = CTS_SCSI_VALID_TQ; >>>>=20 >>>> + /* Prefer connection speed over sas port speed */ >>>> + /* cts->xport_specific.sas.bitrate =3D 0; */ >>>> + cts->xport_specific.sas.valid =3D 0; >>>> + >>>> ccb_h->status =3D CAM_REQ_CMP; >>>> xpt_done(ccb); >>>> ``` >>>>=20 >>>> Things come clear and I know why this weird speed happens, now it = is time to decide how to fix it. >>>>=20 >>>> Fixing the consumer of cam, aka pvscsi driver, is quite simple and = promising. I did a quick search it appears other consumers set = `cts->xport_specific.sas.valid` correctly. It does not convince me as = I'm quite new to cam subsystem. >>>>=20 >>>> Yes. sas.valid is set when the sas.bitrate and other data has been = set correctly. Setting it to 0 like this ensures it's ignored. So if = you know the speed, set sas.bitrate to that speed and sas.valid to 1. >>>=20 >>> That is clear. >>>=20 >>>>=20 >>>> I'm not sure I answered the question right, but if not, please = clarify or point out what I missed and I'll try again. >>>> =20 >>>> Which one do you prefer, MFC commits to stable/13, or do direct fix = for pvscsi driver to stable/13 ? >>>>=20 >>>> [[ Sorry for the delay, I missed this all month ]] >>>>=20 >>>> I generally prefer a MFC, unless the code is no longer in -current.=20= >>>=20 >>> The code live in -current and all supported stable branches. >>>=20 >>>> Even if there's two different fixes for this logical bug, fixing it = in current, then MFCing that (with the current hash) is fine, even if = the stable/13 changes are completely different.=20 >>>=20 >>> The bug does not exist in current and stable/14 but only in = stable/13, due to Edward's work ( commits those zero stack-allocated = CCBs ) were not MFCed into stable/13 branch. >>>=20 >>>> For stable/13 I guess it matters a bit less than stable/14 since = I'll be merging to it less, but if it's a commit from -current that = doesn't need to be made to -stable because of the new commit on stable, = I tend to include the MFC hash text. >>>=20 >>> Do you mean the `cherry picked from commit` commit message ? >>>=20 >>>>=20 >>>> Warner >>>=20 >>>=20 >>> I'm preparing and testing the MFCing. Bless me to not make things = messed up :) >>=20 >> And the individual fix for pvscsi is posted to = https://reviews.freebsd.org/D48438 <https://reviews.freebsd.org/D48438>; = . >=20 > Landed in -current. Will be MFCed to stable/13 after a few days. >=20 >>=20 >>>=20 >>> Best regards, >>> Zhenlei >=20 >=20 >=20 --Apple-Mail=_C93059E6-FA1F-4D0E-866B-7EA4A7E58A8D Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 <html><head><meta http-equiv=3D"Content-Type" content=3D"text/html; = charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; = -webkit-nbsp-mode: space; line-break: after-white-space;" class=3D""><br = class=3D""><div><br class=3D""><blockquote type=3D"cite" class=3D""><div = class=3D"">On Jan 15, 2025, at 12:37 PM, Warner Losh <<a = href=3D"mailto:imp@bsdimp.com" class=3D"">imp@bsdimp.com</a>> = wrote:</div><br class=3D"Apple-interchange-newline"><div class=3D""><div = dir=3D"auto" class=3D"">Great. This looks = good.</div></div></blockquote><div><br class=3D""></div><div>MFSing is = done, along with the following commits those clear the stack allocated = CCBs.</div><div><br class=3D""></div><div><div>076686fe0703 cam: make = sure to clear CCBs allocated on the stack</div><div>ec5325dbca62 cam: = make sure to clear even more CCBs allocated on the = stack</div><div>0f206cc91279 cam: add missing zeroing of a = stack-allocated CCB.</div><div>616a676a0535 cam: clear stack-allocated = CCB in the target layer</div><div><br class=3D""></div><div>Everything = looks good so far.</div><div><br class=3D""></div><div><div = style=3D"caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">Best = regards,</div><div style=3D"caret-color: rgb(0, 0, 0); color: rgb(0, 0, = 0);">Zhenlei</div></div></div><br class=3D""><blockquote type=3D"cite" = class=3D""><div class=3D""><div dir=3D"auto" class=3D""><div dir=3D"auto" = class=3D""><br class=3D""></div><div dir=3D"auto" = class=3D"">Warner</div></div><br class=3D""><div class=3D"gmail_quote = gmail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Tue, Jan = 14, 2025, 9:36=E2=80=AFPM Zhenlei Huang <<a = href=3D"mailto:zlei@freebsd.org" class=3D"">zlei@freebsd.org</a>> = wrote:<br class=3D""></div><blockquote class=3D"gmail_quote" = style=3D"margin:0 0 0 .8ex;border-left:1px #ccc = solid;padding-left:1ex"><div = style=3D"word-wrap:break-word;line-break:after-white-space" class=3D""><br= class=3D""><div class=3D""><br class=3D""><blockquote type=3D"cite" = class=3D""><div class=3D"">On Jan 13, 2025, at 5:06 PM, Zhenlei Huang = <<a href=3D"mailto:zlei@FreeBSD.org" target=3D"_blank" = rel=3D"noreferrer" class=3D"">zlei@FreeBSD.org</a>> wrote:</div><br = class=3D""><div class=3D""><br class=3D""><br = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><blockquote type=3D"cite" = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><div class=3D"">On Jan 13, 2025, at 4:22 PM, = Zhenlei Huang <<a href=3D"mailto:zlei@FreeBSD.org" target=3D"_blank" = rel=3D"noreferrer" class=3D"">zlei@FreeBSD.org</a>> wrote:</div><br = class=3D""><div class=3D""><div = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><br class=3D""><br class=3D""><blockquote = type=3D"cite" class=3D""><div class=3D"">On Dec 28, 2024, at 6:03 AM, = Warner Losh <<a href=3D"mailto:imp@bsdimp.com" target=3D"_blank" = rel=3D"noreferrer" class=3D"">imp@bsdimp.com</a>> wrote:</div><br = class=3D""><div class=3D""><br class=3D""><br = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><div class=3D"gmail_quote" = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none"><div dir=3D"ltr" class=3D"gmail_attr">On Mon, Dec 2, = 2024 at 2:41=E2=80=AFAM Zhenlei Huang <<a = href=3D"mailto:zlei@freebsd.org" target=3D"_blank" rel=3D"noreferrer" = class=3D"">zlei@freebsd.org</a>> wrote:<br class=3D""></div><blockquote= class=3D"gmail_quote" style=3D"margin:0px 0px 0px = 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(= 204,204,204);padding-left:1ex">Hi Warner,<br class=3D""><br = class=3D"">Recently I upgraded some ESXi vms from 13.3 to 13.4 and = noticed weird report for sas speed.<br class=3D"">The boot console has = the following,<br class=3D""><br class=3D"">```<br class=3D"">da0 at = pvscsi0 bus 0 scbus2 target 0 lun 0<br class=3D"">da0: <VMware = Virtual disk 2.0> Fixed Direct Access SPC-4 SCSI device<br = class=3D"">da0: 4294967.295MB/s transfers<br class=3D"">```<br = class=3D"">But camcontrol report the correct value,<br class=3D"">```<br = class=3D""># camcontrol inquiry da0 -R<br class=3D"">pass1: 750.000MB/s = transfers, Command Queueing Enabled<br class=3D"">```<br class=3D""><br = class=3D"">The `4294967.295MB` is actually 0xffff_ffff or -1 but I do = not see any logic set those values.<br class=3D""><br class=3D"">Finally = I managed to get the stack trace,<br class=3D"">```<br = class=3D"">_scsi_announce_periph<br = class=3D"">scsi_announce_periph_sbuf<br = class=3D"">xpt_announce_periph_sbuf<br class=3D"">dadone_proberc<br = class=3D"">xpt_done_process<br class=3D"">xpt_done_td<br = class=3D"">fork_exit<br class=3D"">fork_trampoline<br class=3D"">```<br = class=3D""><br class=3D"">and noticed that the last param `cts` of = `_scsi_announce_periph(struct cam_periph *periph, u_int *speed, u_int = *freq, struct ccb_trans_settings *cts)`<br class=3D"">is from kernel = stack and is not properly initialized, latter I found some commits = related to this,<br class=3D""><br class=3D"">076686fe0703 cam: make = sure to clear CCBs allocated on the stack<br class=3D"">ec5325dbca62 = cam: make sure to clear even more CCBs allocated on the stack<br = class=3D"">0f206cc91279 cam: add missing zeroing of a stack-allocated = CCB.<br class=3D"">616a676a0535 cam: clear stack-allocated CCB in the = target layer<br class=3D""><br class=3D"">I applied them to stable/13, = rebuild and reboot, now the speed of da0 is reported correctly. I also = tried to patch the pvscsi driver with few lines and<br class=3D"">it = also works as intended.<br class=3D""><br class=3D"">```<br class=3D"">---= a/sys/dev/vmware/pvscsi/pvscsi.c<br class=3D"">+++ = b/sys/dev/vmware/pvscsi/pvscsi.c<br class=3D"">@@ -1444,6 +1444,10 @@ = pvscsi_action(struct cam_sim *sim, union ccb *ccb)<br class=3D""> = <span = class=3D""> </span>cts->proto_specific.scsi.flags =3D = CTS_SCSI_FLAGS_TAG_ENB;<br class=3D""> = <span = class=3D""> </span>cts->proto_specific.scsi.valid =3D = CTS_SCSI_VALID_TQ;<br class=3D""><br class=3D"">+ = /* Prefer connection speed over sas = port speed */<br class=3D"">+ = /* cts->xport_specific.sas.bitrate =3D 0; */<br = class=3D"">+ = cts->xport_specific.sas.valid =3D 0;<br class=3D"">+<br = class=3D""> <span = class=3D""> </span>ccb_h->status =3D CAM_REQ_CMP;<br = class=3D""> <span = class=3D""> </span>xpt_done(ccb);<br class=3D"">```<br class=3D""><br= class=3D"">Things come clear and I know why this weird speed happens, = now it is time to decide how to fix it.<br class=3D""><br = class=3D"">Fixing the consumer of cam, aka pvscsi driver, is quite = simple and promising. I did a quick search it appears other consumers = set `cts->xport_specific.sas.valid` correctly. It does not convince = me as I'm quite new to cam subsystem.<br class=3D""></blockquote><div = class=3D""><br class=3D""></div><div class=3D"">Yes. sas.valid is set = when the sas.bitrate and other data has been set correctly. Setting it = to 0 like this ensures it's ignored. So if you know the speed, set = sas.bitrate to that speed and sas.valid to = 1.</div></div></div></blockquote><div class=3D""><br class=3D""></div><div= class=3D"">That is clear.</div><br class=3D""><blockquote type=3D"cite" = class=3D""><div class=3D""><div class=3D"gmail_quote" = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none"><div class=3D""><br class=3D""></div><div class=3D"">I'm = not sure I answered the question right, but if not, please clarify or = point out what I missed and I'll try again.</div><div = class=3D""> </div><blockquote class=3D"gmail_quote" = style=3D"margin:0px 0px 0px = 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(= 204,204,204);padding-left:1ex">Which one do you prefer, MFC commits to = stable/13, or do direct fix for pvscsi driver to stable/13 ?<br = class=3D""></blockquote><div class=3D""><br class=3D""></div><div = class=3D"">[[ Sorry for the delay, I missed this all month ]]</div><div = class=3D""><br class=3D""></div><div class=3D"">I generally prefer a = MFC, unless the code is no longer in -current.<span = class=3D""> </span></div></div></div></blockquote><div class=3D""><br= class=3D""></div><div class=3D"">The code live in -current and all = supported stable branches.</div><br class=3D""><blockquote type=3D"cite" = class=3D""><div class=3D""><div class=3D"gmail_quote" = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none"><div class=3D"">Even if there's two different fixes for = this logical bug, fixing it in current, then MFCing that (with the = current hash) is fine, even if the stable/13 changes are completely = different.<span = class=3D""> </span></div></div></div></blockquote><div class=3D""><br= class=3D""></div><div class=3D"">The bug does not exist in current and = stable/14 but only in stable/13, due to Edward's work ( commits those = zero stack-allocated CCBs ) were not MFCed into stable/13 = branch.</div><div class=3D""><br class=3D""></div><blockquote = type=3D"cite" class=3D""><div class=3D""><div class=3D"gmail_quote" = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none"><div class=3D"">For stable/13 I guess it matters a bit = less than stable/14 since I'll be merging to it less, but if it's a = commit from -current that doesn't need to be made to -stable because of = the new commit on stable, I tend to include the MFC hash = text.</div></div></div></blockquote><div class=3D""><br = class=3D""></div><div class=3D"">Do you mean the `cherry picked from = commit` commit message ?</div><br class=3D""><blockquote type=3D"cite" = class=3D""><div class=3D""><div class=3D"gmail_quote" = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none"><div class=3D""><br class=3D""></div><div = class=3D"">Warner</div></div></div></blockquote></div><div = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><br class=3D""></div><div = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D"">I'm preparing and testing the MFCing. Bless = me to not make things messed up :)</div></div></blockquote><div = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><br class=3D""></div><div = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D"">And the individual fix for pvscsi is posted = to <a href=3D"https://reviews.freebsd.org/D48438" target=3D"_blank" = rel=3D"noreferrer" = class=3D"">https://reviews.freebsd.org/D48438</a> .</div></div></bloc= kquote><div class=3D""><br class=3D""></div><div class=3D"">Landed in = -current. Will be MFCed to stable/13 after a few days.</div><br = class=3D""><blockquote type=3D"cite" class=3D""><div class=3D""><br = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><blockquote type=3D"cite" = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><div class=3D""><br = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><div = style=3D"font-family:Helvetica;font-size:13px;font-style:normal;font-varia= nt-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text= -indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-d= ecoration:none" class=3D""><div class=3D"">Best regards,</div><div = class=3D"">Zhenlei</div></div></div></blockquote></div></blockquote></div>= <br class=3D""><div class=3D""> <div class=3D""><br class=3D""></div> </div> <br class=3D""></div></blockquote></div> </div></blockquote></div><br class=3D""><div class=3D""> <div><br class=3D""></div> </div> <br class=3D""></body></html>= --Apple-Mail=_C93059E6-FA1F-4D0E-866B-7EA4A7E58A8D--
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