On 11/27/2012 12:43, Andre Oppermann wrote: > On 27.11.2012 19:27, Alan Cox wrote: >> On 11/27/2012 12:08, Andre Oppermann wrote: >>> On 27.11.2012 17:42, Alan Cox wrote: >>>> On 11/27/2012 09:06, Konstantin Belousov wrote: >>>>> On Tue, Nov 27, 2012 at 12:26:44PM +0100, Andre Oppermann wrote: >>>>>> FreeBSD bbb.ccc 10.0-CURRENT FreeBSD 10.0-CURRENT #0: >>>>>> Fri Nov 23 17:00:40 CET 2012 >>>>>> aaa_at_bbb.ccc:/usr/obj/usr/src/head/sys/GENERIC amd64 >>>>>> >>>>>> #0 doadump (textdump=-2014022336) at pcpu.h:229 >>>>>> #1 0xffffffff8033e2d2 in db_fncall (dummy1=<value optimized out>, >>>>>> dummy2=<value optimized out>, >>>>>> dummy3=<value optimized out>, dummy4=<value optimized out>) >>>>>> at /usr/src/head/sys/ddb/db_command.c:578 >>>>>> #2 0xffffffff8033e074 in db_command (last_cmdp=<value optimized >>>>>> out>, >>>>>> cmd_table=<value optimized out>, dopager=1) at >>>>>> /usr/src/head/sys/ddb/db_command.c:449 >>>>>> #3 0xffffffff8033dd62 in db_command_loop () at >>>>>> /usr/src/head/sys/ddb/db_command.c:502 >>>>>> #4 0xffffffff80340690 in db_trap (type=<value optimized out>, >>>>>> code=0) >>>>>> at /usr/src/head/sys/ddb/db_main.c:231 >>>>>> #5 0xffffffff808b375e in kdb_trap (type=3, code=0, tf=<value >>>>>> optimized >>>>>> out>) >>>>>> at /usr/src/head/sys/kern/subr_kdb.c:654 >>>>>> #6 0xffffffff80bfc71a in trap (frame=0xffffff8487f478a0) >>>>>> at /usr/src/head/sys/amd64/amd64/trap.c:579 >>>>>> #7 0xffffffff80be65b2 in calltrap () at /tmp/exception-3nQ6Cf.s:179 >>>>>> #8 0xffffffff808b2f5e in kdb_enter (why=0xffffffff80e5e23b "panic", >>>>>> msg=<value optimized out>) >>>>>> at cpufunc.h:63 >>>>>> #9 0xffffffff8088086f in panic (fmt=<value optimized out>) >>>>>> at /usr/src/head/sys/kern/kern_shutdown.c:628 >>>>>> #10 0xffffffff80adea4a in vm_object_madvise (object=<value >>>>>> optimized out>, >>>>>> pindex=<value optimized out>, end=8952, advise=<value >>>>>> optimized out>) >>>>>> at /usr/src/head/sys/vm/vm_object.c:1101 >>>>>> #11 0xffffffff80ad759a in vm_map_madvise (map=0xfffffe0018260188, >>>>>> start=<value optimized out>, >>>>>> end=<value optimized out>, behav=5) at >>>>>> /usr/src/head/sys/vm/vm_map.c:2140 >>>>>> #12 0xffffffff80adbd8d in sys_madvise (td=<value optimized out>, >>>>>> uap=<value optimized out>) >>>>>> at /usr/src/head/sys/vm/vm_mmap.c:752 >>>>>> #13 0xffffffff80bfd3a5 in amd64_syscall (td=0xfffffe0018230000, >>>>>> traced=0) at subr_syscall.c:135 >>>>>> #14 0xffffffff80be689b in Xfast_syscall () at >>>>>> /tmp/exception-3nQ6Cf.s:329 >>>>>> #15 0x00000000016f3bfa in ?? () >>>>> I think this is an omission in the check for the object types. BTW, >>>>> this >>>>> pattern already repeats in several places, I thought about adding >>>>> either >>>>> new pager method, like boolean_t vm_pager_is_pageable(), or just a >>>>> flag >>>>> fields to the struct vm_pager to classify the vm objects. >>>> >>>> >>>> A fictitious page should always have a non-zero wire count. In >>>> fact, it >>>> should always be one and never change. (See vm_page_unwire().) In >>>> vm_object_madvise(), there is a check against the page's wire count >>>> that >>>> precedes the KASSERT(). This check should prevent the KASSERT() from >>>> being reached for the various device-backed object types. So, >>>> something >>>> else has gone wrong here, or rather something has gone wrong elsewhere >>>> that caused the KASSERT() failure here. >>>> >>>> Andre, can we see the contents of the offending struct vm_page and >>>> also >>>> the struct vm_object to which the offending page belongs to? Also, >>>> are >>>> you running a kernel with any experimental zero-copy send support? >>> >>> No experimental zero-copy support, or anything else, just a stock >>> GENERIC kernel. >>> >>> (kgdb) frame 11 >>> #11 0xffffffff80ad759a in vm_map_madvise (map=0xfffffe0018260188, >>> start=<value optimized out>, >>> end=<value optimized out>, behav=5) at >>> /usr/src/head/sys/vm/vm_map.c:2140 >>> 2140 >>> vm_object_madvise(current->object.vm_object, pstart, >>> (kgdb) p *map >>> $1 = {header = {prev = 0xfffffe025631c438, next = 0xfffffe0248f119d8, >>> left = 0x0, right = 0x0, >>> start = 4096, end = 140737488355328, avail_ssize = 0, adj_free = >>> 0, max_free = 0, object = { >>> vm_object = 0x0, sub_map = 0x0}, offset = 0, eflags = 0, >>> protection = 0 '\0', >>> max_protection = 0 '\0', inheritance = 0 '\0', read_ahead = 0 >>> '\0', wired_count = 0, >>> next_read = 0, cred = 0x0}, lock = {lock_object = { >>> lo_name = 0xffffffff80e66905 "vm map (user)", lo_flags = >>> 36896768, lo_data = 0, >>> lo_witness = 0xffffff80006c9700}, sx_lock = 17}, system_mtx = >>> {lock_object = { >>> lo_name = 0xffffffff80e668d7 "vm map (system)", lo_flags = >>> 21168128, lo_data = 0, >>> lo_witness = 0xffffff80006c9500}, mtx_lock = 4}, nentries = 32, >>> size = 64647168, >>> timestamp = 52, needs_wakeup = 0 '\0', system_map = 0 '\0', flags = >>> 0 '\0', >>> root = 0xfffffe02560a6258, pmap = 0xfffffe00182602b8, busy = 0} >>> (kgdb) p* map->pmap >>> $6 = {pm_mtx = {lock_object = {lo_name = 0xffffffff80e66934 "pmap", >>> lo_flags = 21168128, >>> lo_data = 0, lo_witness = 0xffffff80006c9900}, mtx_lock = 4}, >>> pm_pml4 = 0xfffffe0256458000, >>> pm_pvchunk = {tqh_first = 0xfffffe0256142000, tqh_last = >>> 0xfffffe025644c008}, pm_active = { >>> __bits = {1}}, pm_stats = {resident_count = 12683, wired_count >>> = 0}, >>> pm_root = 0xfffffe041289e040} >>> (kgdb) p* map->root >>> $7 = {prev = 0xfffffe0018ed0708, next = 0xfffffe02560a6870, left = >>> 0xfffffe0018ed0708, >>> right = 0xfffffe02560a6870, start = 34393292800, end = 34431041536, >>> avail_ssize = 0, >>> adj_free = 140703057047552, max_free = 140703057047552, object = { >>> vm_object = 0xfffffe0256484570, sub_map = 0xfffffe0256484570}, >>> offset = 1810432, eflags = 0, >>> protection = 3 '\003', max_protection = 7 '\a', inheritance = 1 >>> '\001', read_ahead = 15 '\017', >>> wired_count = 0, next_read = 0, cred = 0x0} >>> >>> (kgdb) p *current >>> $2 = {prev = 0xfffffe025631c438, next = 0xfffffe0248f119d8, left = >>> 0x0, right = 0x0, start = 4096, >>> end = 140737488355328, avail_ssize = 0, adj_free = 0, max_free = 0, >>> object = {vm_object = 0x0, >>> sub_map = 0x0}, offset = 0, eflags = 0, protection = 0 '\0', >>> max_protection = 0 '\0', >>> inheritance = 0 '\0', read_ahead = 0 '\0', wired_count = 0, >>> next_read = 0, cred = 0x0} >>> >>> (kgdb) p *entry >>> $3 = {prev = 0xfffffe0018ed0708, next = 0xfffffe02560a6870, left = >>> 0xfffffe0018ed0708, >>> right = 0xfffffe02560a6870, start = 34393292800, end = 34431041536, >>> avail_ssize = 0, >>> adj_free = 140703057047552, max_free = 140703057047552, object = { >>> vm_object = 0xfffffe0256484570, sub_map = 0xfffffe0256484570}, >>> offset = 1810432, eflags = 0, >>> protection = 3 '\003', max_protection = 7 '\a', inheritance = 1 >>> '\001', read_ahead = 15 '\017', >>> wired_count = 0, next_read = 0, cred = 0x0} >> >> >> The following tells us that this is an OBJT_DEFAULT (i.e., anonymous) >> memory object. Such objects should never contain fictitious pages. Can >> you please print the contents of the offending struct vm_page using the >> address from the panic message? > > (kgdb) p (struct vm_page)*0xfffffe0413c58630 > $12 = {pageq = {tqe_next = 0xfffffe04127fbcc8, tqe_prev = > 0xfffffe0412658358}, listq = { > tqe_next = 0xfffffe0413c586a8, tqe_prev = 0xfffffe0413c585c8}, > left = 0xfffffe0413c585b8, > right = 0xfffffe0413c586a8, object = 0xfffffe0256484570, pindex = > 8868, phys_addr = 10744668160, > md = {pv_list = {tqh_first = 0xfffffe025654d9a0, tqh_last = > 0xfe025654d9a8}, pat_mode = 6}, > queue = 1 '\001', segind = 4 '\004', hold_count = 0, order = 13 > '\r', pool = 0 '\0', cow = 0, > wire_count = 0, aflags = 1 '\001', oflags = 0 '\0', flags = 65535, > act_count = 5 '\005', > busy = 0 '\0', valid = 255 'ÿ', dirty = 0 '\0'} > Except for the value of the "flags" field, this looks like a perfectly ordinary page of physical memory. In other words, this is not a fictitious page. Moreover, there is nothing inconsistent about the other fields. A "flags" field value of 65535 should be an impossibility. We only define flags for 9 of the 16 bits in the field. Is there any chance you're loading and using a kernel module that is older than your kernel?Received on Tue Nov 27 2012 - 18:16:38 UTC
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