Date: Sat, 29 Aug 2020 13:25:16 +0200 From: Michal Meloun <meloun.michal@gmail.com> To: Warner Losh <imp@bsdimp.com> Cc: Mateusz Guzik <mjguzik@gmail.com>, Warner Losh <imp@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all <svn-src-all@freebsd.org>, svn-src-head <svn-src-head@freebsd.org> Subject: Re: svn commit: r364946 - head/sys/kern Message-ID: <213fcb81-ceab-677f-98dc-e8cb33fef7d1@gmail.com> In-Reply-To: <CANCZdfp9m7knXfguYh79fdALBiL3ktEH6e=NU4S2qdOv6ory%2Bg@mail.gmail.com> References: <202008290430.07T4UCM4007928@repo.freebsd.org> <CAGudoHFAkrAykin6ngH=04254J4AmhHk2NmDyGfrUE=wJcxH2A@mail.gmail.com> <CANCZdfqXtKhKhh33ovFQ4_a3tiesRi8-6ZuMTp0yW%2BMzkxWLzA@mail.gmail.com> <f1a67850-e9e5-d785-6562-972aeb9f1206@gmail.com> <CANCZdfp9m7knXfguYh79fdALBiL3ktEH6e=NU4S2qdOv6ory%2Bg@mail.gmail.com>
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On 29.08.2020 13:02, Warner Losh wrote: > On Sat, Aug 29, 2020 at 4:38 AM Michal Meloun <meloun.michal@gmail.com> > wrote: > >> >> >> On 29.08.2020 12:04, Warner Losh wrote: >>> On Sat, Aug 29, 2020 at 1:09 AM Mateusz Guzik <mjguzik@gmail.com> wrote: >>> >>>> This crashes on boot for me: >>>> >>> >>> I wasn't able to get it to crash on boot for me, but I was able to >> recreate >>> it. >> It crashed on ofw based systems where some enumerated devices have not a >> suitable driver, see: >> --------------------------------------- >> sysctl_devices: nameunit: root0, descs: System root bus, driver: root >> sysctl_devices: nameunit: nexus0, descs: (null), driver: nexus >> sysctl_devices: nameunit: ofwbus0, descs: Open Firmware Device Tree, >> driver: ofwbus >> sysctl_devices: nameunit: pcib0, descs: Nvidia Integrated PCI/PCI-E >> Controller, driver: pcib >> sysctl_devices: nameunit: simplebus0, descs: Flattened device tree >> simple bus, driver: simplebus >> sysctl_devices: nameunit: gic0, descs: ARM Generic Interrupt Controller, >> driver: gic >> sysctl_devices: nameunit: (null), descs: (null), driver: >> sysctl_devices: nameunit: lic0, descs: (null), driver: lic >> sysctl_devices: nameunit: (null), descs: (null), driver: >> sysctl_devices: nameunit: car0, descs: Tegra Clock Driver, driver: car >> .... >> ---------------------------------------------------------------------- >>> Fixed in r364949.Confirmed. >> I think it didn't crash on boot for me because >>> kldxref failed due to the segment thing so devmatch didn't run which >> would >>> have triggered this bug. devinfo did trigger a very similar crash, and >>> r364949 fixes that crash. Even a new kldxref failed due to the too many >>> segments thing, so I can't confirm that's what you hit, but I'm pretty >> sure >>> it is... >>> >> But there is another issue in device_sysctl_handler() (not analyzed yet): >> root@tegra210:~ # sysctl dev.cpu. >> dev.cpu.3.temperature: 50.5C >> dev.cpu.3panic: sbuf_clear makes no sense on sbuf 0xffff00006f21a528 >> with drain >> cpuid = 2 >> time = 1598696937 >> KDB: stack backtrace: >> db_trace_self() at db_fetch_ksymtab+0x164 >> pc = 0xffff0000006787f4 lr = 0xffff000000153400 >> sp = 0xffff00006f21a1b0 fp = 0xffff00006f21a3b0 >> >> db_fetch_ksymtab() at vpanic+0x198 >> pc = 0xffff000000153400 lr = 0xffff00000036b274 >> sp = 0xffff00006f21a3c0 fp = 0xffff00006f21a420 >> >> vpanic() at panic+0x44 >> pc = 0xffff00000036b274 lr = 0xffff00000036b018 >> sp = 0xffff00006f21a430 fp = 0xffff00006f21a4e0 >> >> panic() at sbuf_clear+0xa0 >> pc = 0xffff00000036b018 lr = 0xffff0000003c17c8 >> sp = 0xffff00006f21a4f0 fp = 0xffff00006f21a4f0 >> >> sbuf_clear() at sbuf_cpy+0x58 >> pc = 0xffff0000003c17c8 lr = 0xffff0000003c1ff0 >> sp = 0xffff00006f21a500 fp = 0xffff00006f21a500 >> >> sbuf_cpy() at _gone_in_dev+0x560 >> pc = 0xffff0000003c1ff0 lr = 0xffff0000003a9078 >> sp = 0xffff00006f21a510 fp = 0xffff00006f21a570 >> >> _gone_in_dev() at sbuf_new_for_sysctl+0x170 >> pc = 0xffff0000003a9078 lr = 0xffff00000037c1a8 >> sp = 0xffff00006f21a580 fp = 0xffff00006f21a5a0 >> >> sbuf_new_for_sysctl() at kernel_sysctl+0x36c >> pc = 0xffff00000037c1a8 lr = 0xffff00000037b63c >> sp = 0xffff00006f21a5b0 fp = 0xffff00006f21a630 >> > > This traceback is all kinds of crazy. sbuf_new_for_sysctl doesn't call > _gone_in_dev(), which doesn't do sbuf stuff at all. And neither does it > call sbuf_cpy(). Though I get a crash that looks like: > Tracing pid 66442 tid 101464 td 0xfffffe02f47b7c00 > kdb_enter() at kdb_enter+0x37/frame 0xfffffe02f4ae3740 > vpanic() at vpanic+0x19e/frame 0xfffffe02f4ae3790 > panic() at panic+0x43/frame 0xfffffe02f4ae37f0 > sbuf_clear() at sbuf_clear+0xac/frame 0xfffffe02f4ae3800 > sbuf_cpy() at sbuf_cpy+0x5a/frame 0xfffffe02f4ae3820 > device_sysctl_handler() at device_sysctl_handler+0x133/frame > 0xfffffe02f4ae38a0 > sysctl_root_handler_locked() at sysctl_root_handler_locked+0x9c/frame > 0xfffffe02f4ae38f0 > sysctl_root() at sysctl_root+0x20a/frame 0xfffffe02f4ae3970 > userland_sysctl() at userland_sysctl+0x17d/frame 0xfffffe02f4ae3a20 > sys___sysctl() at sys___sysctl+0x5f/frame 0xfffffe02f4ae3ad0 > amd64_syscall() at amd64_syscall+0x140/frame 0xfffffe02f4ae3bf0 > fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe02f4ae3bf0 > --- syscall (202, FreeBSD ELF64, sys___sysctl), rip = 0x80042d50a, rsp = > 0x7fffffffd458, rbp = 0x7fffffffd490 --- > > on a sysctl -a which I think makes more sense... I'll see if I can track > it down... I think it's because sbuf_cpy does an unconditional clear, which > triggers this assert, which is likely bogus for this case. sbuf_cat doesn't > seem to have this issue... I'll confirm and commit. > > Warner Yeah, sorry. Local symbols are not available for netbooted kernel :(. And i csan confirm that problem is cause by using sbuf_cpy() on sbuf allocated by sbuf_new_for_sysctl() (thus with drain handler) in device_sysctl_handler(). But pure replacing sbuf_cpy() by sbuf_cat() gives me another panic: panic: Assertion (sb->s_flags & SBUF_INCLUDENUL) == 0 failed at /usr2/Meloun/git/pmap/sys/kern/subr_bus.c:4936 (still as respose for sysctl dev.cpu) Michal > >> kernel_sysctl() at userland_sysctl+0xf4 >> pc = 0xffff00000037b63c lr = 0xffff00000037bc5c >> sp = 0xffff00006f21a640 fp = 0xffff00006f21a6d0 >> >> userland_sysctl() at sys___sysctl+0x68 >> pc = 0xffff00000037bc5c lr = 0xffff00000037bb28 >> sp = 0xffff00006f21a6e0 fp = 0xffff00006f21a790 >> >> sys___sysctl() at do_el0_sync+0x4e0 >> pc = 0xffff00000037bb28 lr = 0xffff000000697918 >> sp = 0xffff00006f21a7a0 fp = 0xffff00006f21a830 >> >> do_el0_sync() at handle_el0_sync+0x90 >> pc = 0xffff000000697918 lr = 0xffff00000067aa24 >> sp = 0xffff00006f21a840 fp = 0xffff00006f21a980 >> >> handle_el0_sync() at 0x4047764c >> pc = 0xffff00000067aa24 lr = 0x000000004047764c >> sp = 0xffff00006f21a990 fp = 0x0000ffffffffc250 >> >> KDB: enter: panic >> [ thread pid 1263 tid 100092 ] >> Stopped at 0x40477fb4: undefined 54000042 >> >>> Warner >>> >> >>> >>>> atal trap 12: page fault while in kernel mode >>>> cpuid = 0; apic id = 00 >>>> fault virtual address = 0x0 >>>> fault code = supervisor read data, page not present >>>> instruction pointer = 0x20:0xffffffff805b0a7f >>>> stack pointer = 0x28:0xfffffe002366a7f0 >>>> frame pointer = 0x28:0xfffffe002366a7f0 >>>> code segment = base 0x0, limit 0xfffff, type 0x1b >>>> = DPL 0, pres 1, long 1, def32 0, gran 1 >>>> processor eflags = interrupt enabled, resume, IOPL = 0 >>>> current process = 89 (devmatch) >>>> trap number = 12 >>>> panic: page fault >>>> cpuid = 0 >>>> time = 1598692135 >>>> KDB: stack backtrace: >>>> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame >>>> 0xfffffe002366a4a0 >>>> vpanic() at vpanic+0x182/frame 0xfffffe002366a4f0 >>>> panic() at panic+0x43/frame 0xfffffe002366a550 >>>> trap_fatal() at trap_fatal+0x387/frame 0xfffffe002366a5b0 >>>> trap_pfault() at trap_pfault+0x4f/frame 0xfffffe002366a610 >>>> trap() at trap+0x27d/frame 0xfffffe002366a720 >>>> calltrap() at calltrap+0x8/frame 0xfffffe002366a720 >>>> --- trap 0xc, rip = 0xffffffff805b0a7f, rsp = 0xfffffe002366a7f0, rbp >>>> = 0xfffffe002366a7f0 --- >>>> strlen() at strlen+0x1f/frame 0xfffffe002366a7f0 >>>> sbuf_cat() at sbuf_cat+0x15/frame 0xfffffe002366a810 >>>> sysctl_devices() at sysctl_devices+0x104/frame 0xfffffe002366a8a0 >>>> sysctl_root_handler_locked() at sysctl_root_handler_locked+0x91/frame >>>> 0xfffffe002366a8f0 >>>> sysctl_root() at sysctl_root+0x249/frame 0xfffffe002366a970 >>>> userland_sysctl() at userland_sysctl+0x170/frame 0xfffffe002366aa20 >>>> sys___sysctl() at sys___sysctl+0x5f/frame 0xfffffe002366aad0 >>>> amd64_syscall() at amd64_syscall+0x10c/frame 0xfffffe002366abf0 >>>> fast_syscall_common() at fast_syscall_common+0xf8/frame >> 0xfffffe002366abf0 >>>> --- syscall (202, FreeBSD ELF64, sys___sysctl), rip = 0x80041c0ea, rsp >>>> = 0x7fffffffda78, rbp = 0x7fffffffdab0 --- >>>> KDB: enter: panic >>>> [ thread pid 89 tid 100067 ] >>>> Stopped at kdb_enter+0x37: movq $0,0x7e2616(%rip) >>>> >>>> >>>> On 8/29/20, Warner Losh <imp@freebsd.org> wrote: >>>>> Author: imp >>>>> Date: Sat Aug 29 04:30:12 2020 >>>>> New Revision: 364946 >>>>> URL: https://svnweb.freebsd.org/changeset/base/364946 >>>>> >>>>> Log: >>>>> Move to using sbuf for some sysctl in newbus >>>>> >>>>> Convert two different sysctl to using sbuf. First, for all the >> default >>>>> sysctls we implement for each device driver that's attached. This is >> a >>>>> pure sbuf conversion. >>>>> >>>>> Second, convert sysctl_devices to fill its buffer with sbuf rather >>>>> than a hand-rolled crappy thing I wrote years ago. >>>>> >>>>> Reviewed by: cem, markj >>>>> Differential Revision: https://reviews.freebsd.org/D26206 >>>>> >>>>> Modified: >>>>> head/sys/kern/subr_bus.c >>>>> >>>>> Modified: head/sys/kern/subr_bus.c >>>>> >>>> >> ============================================================================== >>>>> --- head/sys/kern/subr_bus.c Sat Aug 29 04:30:06 2020 (r364945) >>>>> +++ head/sys/kern/subr_bus.c Sat Aug 29 04:30:12 2020 (r364946) >>>>> @@ -260,36 +260,33 @@ enum { >>>>> static int >>>>> device_sysctl_handler(SYSCTL_HANDLER_ARGS) >>>>> { >>>>> + struct sbuf sb; >>>>> device_t dev = (device_t)arg1; >>>>> - const char *value; >>>>> - char *buf; >>>>> int error; >>>>> >>>>> - buf = NULL; >>>>> + sbuf_new_for_sysctl(&sb, NULL, 1024, req); >>>>> switch (arg2) { >>>>> case DEVICE_SYSCTL_DESC: >>>>> - value = dev->desc ? dev->desc : ""; >>>>> + sbuf_cpy(&sb, dev->desc ? dev->desc : ""); >>>>> break; >>>>> case DEVICE_SYSCTL_DRIVER: >>>>> - value = dev->driver ? dev->driver->name : ""; >>>>> + sbuf_cpy(&sb, dev->driver ? dev->driver->name : ""); >>>>> break; >>>>> case DEVICE_SYSCTL_LOCATION: >>>>> - value = buf = malloc(1024, M_BUS, M_WAITOK | M_ZERO); >>>>> - bus_child_location_str(dev, buf, 1024); >>>>> + bus_child_location_sb(dev, &sb); >>>>> break; >>>>> case DEVICE_SYSCTL_PNPINFO: >>>>> - value = buf = malloc(1024, M_BUS, M_WAITOK | M_ZERO); >>>>> - bus_child_pnpinfo_str(dev, buf, 1024); >>>>> + bus_child_pnpinfo_sb(dev, &sb); >>>>> break; >>>>> case DEVICE_SYSCTL_PARENT: >>>>> - value = dev->parent ? dev->parent->nameunit : ""; >>>>> + sbuf_cpy(&sb, dev->parent ? dev->parent->nameunit : ""); >>>>> break; >>>>> default: >>>>> + sbuf_delete(&sb); >>>>> return (EINVAL); >>>>> } >>>>> - error = SYSCTL_OUT_STR(req, value); >>>>> - if (buf != NULL) >>>>> - free(buf, M_BUS); >>>>> + error = sbuf_finish(&sb); >>>>> + sbuf_delete(&sb); >>>>> return (error); >>>>> } >>>>> >>>>> @@ -5464,13 +5461,13 @@ SYSCTL_PROC(_hw_bus, OID_AUTO, info, >>>> CTLTYPE_STRUCT >>>>> | >>>>> static int >>>>> sysctl_devices(SYSCTL_HANDLER_ARGS) >>>>> { >>>>> + struct sbuf sb; >>>>> int *name = (int *)arg1; >>>>> u_int namelen = arg2; >>>>> int index; >>>>> device_t dev; >>>>> struct u_device *udev; >>>>> int error; >>>>> - char *walker, *ep; >>>>> >>>>> if (namelen != 2) >>>>> return (EINVAL); >>>>> @@ -5501,34 +5498,21 @@ sysctl_devices(SYSCTL_HANDLER_ARGS) >>>>> udev->dv_devflags = dev->devflags; >>>>> udev->dv_flags = dev->flags; >>>>> udev->dv_state = dev->state; >>>>> - walker = udev->dv_fields; >>>>> - ep = walker + sizeof(udev->dv_fields); >>>>> -#define CP(src) \ >>>>> - if ((src) == NULL) \ >>>>> - *walker++ = '\0'; \ >>>>> - else { \ >>>>> - strlcpy(walker, (src), ep - walker); \ >>>>> - walker += strlen(walker) + 1; \ >>>>> - } \ >>>>> - if (walker >= ep) \ >>>>> - break; >>>>> - >>>>> - do { >>>>> - CP(dev->nameunit); >>>>> - CP(dev->desc); >>>>> - CP(dev->driver != NULL ? dev->driver->name : NULL); >>>>> - bus_child_pnpinfo_str(dev, walker, ep - walker); >>>>> - walker += strlen(walker) + 1; >>>>> - if (walker >= ep) >>>>> - break; >>>>> - bus_child_location_str(dev, walker, ep - walker); >>>>> - walker += strlen(walker) + 1; >>>>> - if (walker >= ep) >>>>> - break; >>>>> - *walker++ = '\0'; >>>>> - } while (0); >>>>> -#undef CP >>>>> - error = SYSCTL_OUT(req, udev, sizeof(*udev)); >>>>> + sbuf_new(&sb, udev->dv_fields, sizeof(udev->dv_fields), >>>> SBUF_FIXEDLEN); >>>>> + sbuf_cat(&sb, dev->nameunit); >>>>> + sbuf_putc(&sb, '\0'); >>>>> + sbuf_cat(&sb, dev->desc); >>>>> + sbuf_putc(&sb, '\0'); >>>>> + sbuf_cat(&sb, dev->driver != NULL ? dev->driver->name : '\0'); >>>>> + sbuf_putc(&sb, '\0'); >>>>> + bus_child_pnpinfo_sb(dev, &sb); >>>>> + sbuf_putc(&sb, '\0'); >>>>> + bus_child_location_sb(dev, &sb); >>>>> + sbuf_putc(&sb, '\0'); >>>>> + error = sbuf_finish(&sb); >>>>> + if (error == 0) >>>>> + error = SYSCTL_OUT(req, udev, sizeof(*udev)); >>>>> + sbuf_delete(&sb); >>>>> free(udev, M_BUS); >>>>> return (error); >>>>> } >>>>> >>>> >>>> >>>> -- >>>> Mateusz Guzik <mjguzik gmail.com> >>>> >>> >> >
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