Date: Wed, 10 Mar 2021 08:25:00 -0700 From: Warner Losh <imp@bsdimp.com> To: David Wolfskill <david@catwhisker.org>, Warner Losh <imp@bsdimp.com>, FreeBSD Current <current@freebsd.org> Subject: Re: "panic: malloc(M_WAITOK) with sleeping prohibited" at main-n245363-b3dac3913dc9 Message-ID: <CANCZdfrhneUEUx3HheuPHNe1B8RcA8McP=tfJnghCBDwncbTxA@mail.gmail.com> In-Reply-To: <YEi9lPwjl5VNogyn@albert.catwhisker.org> References: <YEdlblQdBcjZkcf%2B@albert.catwhisker.org> <CANCZdfqnMktE4uAU%2BOP8ZKyXzupTqPqr21fP1PDk1U%2BJDswhuw@mail.gmail.com> <YEfnRA1WvWtsM8ks@albert.catwhisker.org> <YEfsoSP9rNALWFdR@albert.catwhisker.org> <CANCZdfrZB%2BdE6d30q6PNzVLuH5gcx5vGzTv9BxbP==VDKzgQ=w@mail.gmail.com> <YEi9lPwjl5VNogyn@albert.catwhisker.org>
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On Wed, Mar 10, 2021 at 5:37 AM David Wolfskill <david@catwhisker.org> wrote: > On Tue, Mar 09, 2021 at 04:04:56PM -0700, Warner Losh wrote: > > On Tue, Mar 9, 2021 at 2:46 PM David Wolfskill <david@catwhisker.org> > wrote: > > ... > > > uma_zalloc_debug: zone "malloc-1024"umass0 on uhub2 > > > with the following non-sleepable locks held: > > > umass0: <Bulk-In, Bulk-Out, Interface> on usbus0 > > > exclusive sleep mutex CAM device lockumass0: SCSI over Bulk-Only; > quirks > > > = 0x4000 > > > (CAM device lock) r = 0 (0xfffff800122c9cd0) locked @ > > > /usr/src/sys/cam/cam_xpt.c:2333 > > > umass0:6:0: Attached to scbus6 > > > stack backtrace: > > > (probe0:umass-sim0:0:0:0): Down reving Protocol Version from 2 to 0? > > > #0 0xffffffff80c7cce1 at witnesuhub3: 6 ports with 6 removable, self > > > powered > > > s_debugger+0x71 > > > pass6 at umass-sim0 bus 0 scbus6 target 0 lun 0 > > > #1 0xffffffff80pass6: uhub4: 8 ports with 8 removable, self powered > > > c7ddfd at witness_warn+0x40d > > > #2<Generic- Compact Flash 1.00> Removable Direct Access SCSI device > > > 0xffffffff80f42fe6 at uma_zallpass6: Serial Number 20100818841300000 > > > oc_arg+0x46 > > > #3 0xffffffff80be34pass6: 40.000MB/s transfers > > > panic: malloc(M_WAITOK) with sleeping prohibited > > > cpuid = 1 > > > time = 22 > > > KDB: stack backtrace: > > > db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame > > > 0xfffffe00e157a2d0 > > > vpanic() at vpanic+0x181/frame 0xfffffe00e157a320 > > > panic() at panic+0x43/frame 0xfffffe00e157a380 > > > malloc_dbg() at malloc_dbg+0xd4/frame 0xfffffe00e157a3a0 > > > malloc() at malloc+0x34/frame 0xfffffe00e157a400 > > > g_post_event_x() at g_post_event_x+0x5a/frame 0xfffffe00e157a450 > > > g_post_event() at g_post_event+0x48/frame 0xfffffe00e157a4b0 > > > disk_create() at disk_create+0x16f/frame 0xfffffe00e157a600 > > > daregister() at daregister+0x70a/frame 0xfffffe00e157a880 > > > cam_periph_alloc() at cam_periph_alloc+0x57b/frame 0xfffffe00e157a950 > > > daasync() at daasync+0x2c2/frame 0xfffffe00e157a9c0 > > > xpt_async_process_dev() at xpt_async_process_dev+0x152/frame > > > 0xfffffe00e157aa10 > > > xpt_async_process() at xpt_async_process+0x334/frame 0xfffffe00e157ab20 > > > xpt_done_process() at xpt_done_process+0x3a3/frame 0xfffffe00e157ab60 > > > xpt_done_td() at xpt_done_td+0xf5/frame 0xfffffe00e157abb0 > > > fork_exit() at fork_exit+0x80/frame 0xfffffe00e157abf0 > > > fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe00e157abf0 > > > --- trap 0, rip = 0, rsp = 0, rbp = 0 --- > > > KDB: enter: panic > > > [ thread pid 17 tid 100095 ] > > > Stopped at kdb_enter+0x37: movq $0,0x128b8ce(%rip) > > > db> > > > > > I'm willing to "poke at it" a bit, given a hint or two... > > > > > > > OK. I know what's happening here. disk_create() posts an event and also > > expects to sleep to get memory. I can fix that too, but then that's one > > more 'no memory' hole. > > > > I'm unsure if we should keep playing whack-a-mole, or just defer this > > creation to the taskqueue we already have hanging around... > > > > Warner > > .... > > Same (build) machine had a similar panic after updating source to > main-n245372-d1cbe7908986 & rebuilding. FWIW. > > Also (as yesterday), neither laptop exhibited a problem after the > corresponding update. > Yes it "works" without invariants. I'm working on a better fix that isn't such a huge game of whack-a-mole that defers the async messages to an taskqueue where they can sleep for memory, if need be. Warner > Peace, > david > -- > David H. Wolfskill david@catwhisker.org > It is supremely disingenuous to claim a lack of jurisdiction, then > proceed to participate in a decision on the same matter. > > See https://www.catwhisker.org/~david/publickey.gpg for my public key. >
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