Date: Mon, 16 Feb 1998 20:57:36 +0100 From: Tor Egge <Tor.Egge@idi.ntnu.no> To: toor@dyson.iquest.net Cc: freebsd@isvara.net, hackers@FreeBSD.ORG Subject: Re: VM messed: vm_page_free panic problem Message-ID: <199802161957.UAA07226@pat.idi.ntnu.no> In-Reply-To: Your message of "Sat, 14 Feb 1998 12:35:13 -0500 (EST)" References: <199802141735.MAA06202@dyson.iquest.net>
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> freebsd@isvara.net said:
> > Hi,
> > I'm experiencing a problem with the freebsd-current bootdisks since
> > a weeks ago. I get the error:
> > vm_page_free: pindex(12), busy(0), PG_BUSY(0), hold(0)
> > panic: vm_page_free: freeing page
> >
> > There is clearly a problem with the VM subsystem, and there have been a
> > few messages posted here with people pointing this out. Since this stops
> > people installing the latest freebsd-current, it could be considered
> > quite important.
> >
> I'll try to look at it, but I am going to be very busy again next week.
> If someone else gets a chance to look into it, it would be helpful.
vnode_pager_getpages first called ffs_getpages. ffs_getpages assumes
that the underlying device has a getpages operation, and performes
some operations (e.g. freeing the 4 last pages passed to ffs_getpages).
Then the VOP_GETPAGES routine returns EOPNOTSUPP, and ffs_getpages
returns this error code.
vnode_pager_getpages assumes that the call to VOP_GETPAGES had no
side effects, and proceeds to call vnode_pager_leaf_getpages which
attempts to free the last 4 pages once more (with a panic as the
result).
I suggest adding a getpages operation to mfs, e.g. applying the
appended patch.
---
#0 boot (howto=260) at ../../kern/kern_shutdown.c:285
(kgdb) where
#0 boot (howto=260) at ../../kern/kern_shutdown.c:285
#1 0xf0118847 in panic (fmt=0xf01013f8 "from debugger")
at ../../kern/kern_shutdown.c:425
#2 0xf0101415 in db_panic (addr=-264640668, have_addr=0, count=-1,
modif=0xf61bab58 "") at ../../ddb/db_command.c:432
#3 0xf01012f5 in db_command (last_cmdp=0xf0226aa4, cmd_table=0xf0226904,
aux_cmd_tablep=0xf039ecb0) at ../../ddb/db_command.c:332
#4 0xf0101482 in db_command_loop () at ../../ddb/db_command.c:454
#5 0xf0103b43 in db_trap (type=3, code=0) at ../../ddb/db_trap.c:71
#6 0xf01bb921 in kdb_trap (type=3, code=0, regs=0xf61bac44)
at ../../i386/i386/db_interface.c:157
#7 0xf01c8e38 in trap (frame={tf_es = 16, tf_ds = 16, tf_edi = 0,
tf_esi = -266674698, tf_ebp = -165958520, tf_isp = -165958548,
tf_ebx = 256, tf_edx = -266618091, tf_ecx = 0, tf_eax = 18,
tf_trapno = 3, tf_err = 0, tf_eip = -266618035, tf_cs = 8,
tf_eflags = 598, tf_esp = -266618107, tf_ss = -267286564})
at ../../i386/i386/trap.c:474
#8 0xf01bbb4d in Debugger (msg=0xf01187dc "panic")
at ../../i386/i386/db_interface.c:316
#9 0xf011883e in panic (fmt=0xf01addf6 "vm_page_free: freeing free page")
at ../../kern/kern_shutdown.c:423
#10 0xf01adecd in vm_page_freechk_and_unqueue (m=0xf093ed98)
at ../../vm/vm_page.c:1048
#11 0xf01adfc4 in vm_page_free (m=0xf093ed98) at ../../vm/vm_page.c:1135
#12 0xf01b15ff in vnode_pager_freepage (m=0xf093ed98)
at ../../vm/vnode_pager.c:318
#13 0xf01b1e63 in vnode_pager_leaf_getpages (object=0xf03afda4, m=0xf61badb4,
count=16, reqpage=0) at ../../vm/vnode_pager.c:656
#14 0xf01b1b55 in vnode_pager_getpages (object=0xf03afda4, m=0xf61badb4,
count=16, reqpage=0) at ../../vm/vnode_pager.c:542
#15 0xf01b08a3 in vm_pager_get_pages (object=0xf03afda4, m=0xf61badb4,
count=16, reqpage=0) at ../../vm/vm_pager.c:182
#16 0xf01118ea in exec_map_first_page (imgp=0xf61bae90)
at ../../kern/kern_exec.c:394
#17 0xf011140e in execve (p=0xf61b4ec0, uap=0xf61baf98)
at ../../kern/kern_exec.c:173
#18 0xf010d128 in start_init (p=0xf61b4ec0) at ../../kern/init_main.c:639
#19 0xf010cf56 in kthread_init (dummy=0x0) at ../../kern/init_main.c:532
#20 0xf01bcbe3 in fork_trampoline ()
Cannot access memory at address 0x1ffff000.
(kgdb) up 15
#15 0xf01b08a3 in vm_pager_get_pages (object=0xf03afda4, m=0xf61badb4,
count=16, reqpage=0) at ../../vm/vm_pager.c:182
(kgdb) down
#14 0xf01b1b55 in vnode_pager_getpages (object=0xf03afda4, m=0xf61badb4,
count=16, reqpage=0) at ../../vm/vnode_pager.c:542
(kgdb) list
537 struct vnode *vp;
538
539 vp = object->handle;
540 rtval = VOP_GETPAGES(vp, m, count*PAGE_SIZE, reqpage, 0);
541 if (rtval == EOPNOTSUPP)
542 return vnode_pager_leaf_getpages(object, m, count, reqpage);
543 else
544 return rtval;
545 }
546
(kgdb) print vop_getpages_desc
$1 = {vdesc_offset = 40, vdesc_name = 0xf01006c4 "vop_getpages",
vdesc_flags = 0, vdesc_vp_offsets = 0xf0226728, vdesc_vpp_offset = -1,
vdesc_cred_offset = -1, vdesc_proc_offset = -1,
vdesc_componentname_offset = -1, vdesc_transports = 0x0}
(kgdb) print vp
$2 = (struct vnode *) 0x0
(kgdb) print ((struct vnode *) object->handle)->v_op[40]
$3 = (int (*)()) 0xf019c17c <ffs_getpages>
(kgdb)
-----
Index: mfs_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/ufs/mfs/mfs_vnops.c,v
retrieving revision 1.34
diff -u -r1.34 mfs_vnops.c
--- mfs_vnops.c 1998/01/01 12:40:25 1.34
+++ mfs_vnops.c 1998/02/16 18:57:06
@@ -56,6 +56,7 @@
static int mfs_reclaim __P((struct vop_reclaim_args *)); /* XXX */
static int mfs_print __P((struct vop_print_args *)); /* XXX */
static int mfs_strategy __P((struct vop_strategy_args *)); /* XXX */
+static int mfs_getpages __P((struct vop_getpages_args *)); /* XXX */
/*
* mfs vnode operations.
*/
@@ -66,7 +67,7 @@
{ &vop_bwrite_desc, (vop_t *) vop_defaultop },
{ &vop_close_desc, (vop_t *) mfs_close },
{ &vop_fsync_desc, (vop_t *) mfs_fsync },
- { &vop_getpages_desc, (vop_t *) vop_defaultop },
+ { &vop_getpages_desc, (vop_t *) mfs_getpages },
{ &vop_inactive_desc, (vop_t *) mfs_inactive },
{ &vop_ioctl_desc, (vop_t *) vop_enotty },
{ &vop_islocked_desc, (vop_t *) vop_defaultop },
@@ -310,4 +311,13 @@
i = vop_defaultop(ap);
printf("mfs_badop[%s] = %d\n", ap->a_desc->vdesc_name,i);
return (i);
+}
+
+
+static int
+mfs_getpages(ap)
+ struct vop_getpages_args *ap;
+{
+
+ return (VOCALL(spec_vnodeop_p, VOFFSET(vop_getpages), ap));
}
- Tor Egge
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