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 *entry->object.vm_object > $4 = {mtx = {lock_object = {lo_name = 0xffffffff80e66913 "vm object", > lo_flags = 21168128, > lo_data = 0, lo_witness = 0xffffff80006cdd00}, mtx_lock = > 18446741875091243008}, > object_list = {tqe_next = 0xfffffe0248ffb910, tqe_prev = > 0xfffffe025618e020}, shadow_head = { > lh_first = 0x0}, shadow_list = {le_next = 0x0, le_prev = 0x0}, > memq = { > tqh_first = 0xfffffe0413891880, tqh_last = 0xfffffe0413a3a570}, > root = 0xfffffe0413c58630, > size = 9658, generation = 1, ref_count = 1, shadow_count = 0, > memattr = 6 '\006', type = 0 '\0', > flags = 12288, pg_color = 7750, paging_in_progress = 0, > resident_page_count = 7650, > backing_object = 0x0, backing_object_offset = 0, pager_object_list = > {tqe_next = 0x0, > tqe_prev = 0x0}, rvq = {lh_first = 0xfffffe0400ff07c0}, cache = > 0x0, handle = 0x0, un_pager = { > vnp = {vnp_size = 0, writemappings = 0}, devp = {devp_pglist = > {tqh_first = 0x0, > tqh_last = 0x0}, ops = 0x0}, sgp = {sgp_pglist = {tqh_first = > 0x0, tqh_last = 0x0}}, > swp = {swp_bcount = 0}}, cred = 0xfffffe0018244c00, charge = > 39559168} > (kgdb) p *entry->object.sub_map > $5 = {header = {prev = 0xffffffff80e66913, next = 0x1430000, left = > 0xffffff80006cdd00, > right = 0xfffffe0018230000, start = 18446741884500949264, end = > 18446741884720701472, > avail_ssize = 0, adj_free = 0, max_free = 0, object = {vm_object = > 0xfffffe0413891880, > sub_map = 0xfffffe0413891880}, offset = -2181513894544, eflags = > 331712048, > protection = 4 '\004', max_protection = 254 'þ', inheritance = -1 > 'ÿ', read_ahead = 255 'ÿ', > wired_count = 9658, next_read = 4294967297, cred = > 0x3000000600000000}, lock = {lock_object = { > lo_name = 0x1e46 <Address 0x1e46 out of bounds>, lo_flags = > 7650, lo_data = 0, > lo_witness = 0x0}, sx_lock = 0}, system_mtx = {lock_object = > {lo_name = 0x0, lo_flags = 0, > lo_data = 0, lo_witness = 0xfffffe0400ff07c0}, mtx_lock = 0}, > nentries = 0, size = 0, > timestamp = 0, needs_wakeup = 0 '\0', system_map = 0 '\0', flags = 0 > '\0', root = 0x0, > pmap = 0xfffffe0018244c00, busy = 39559168} > (kgdb) p *entry->object.sub_map->pmap > $8 = {pm_mtx = {lock_object = {lo_name = 0x3e900000114 <Address > 0x3e900000114 out of bounds>, > lo_flags = 1001, lo_data = 1001, lo_witness = 0x3e900000003}, > mtx_lock = 1001}, > pm_pml4 = 0xfffffe0018e53c00, pm_pvchunk = {tqh_first = > 0xfffffe0018e53c00, > tqh_last = 0xffffffff811e74a0}, pm_active = {__bits = > {-2198902153216}}, pm_stats = { > resident_count = 0, wired_count = 0}, pm_root = 0x0} >Received on Tue Nov 27 2012 - 17:35:58 UTC
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