Bob Montgomery wrote:
With respect to character devices:
> ... [snip] ...
I can come up with believable file_ops values for (most? all?) of the
others. And this leads me to wonder if crash shouldn't be collecting
this info in a similar manner to fill in the other OPERATIONS fields.
But now I'm quite a bit past what I know about how the character device
stuff works.
Thanks,
Bob Montgomery
Working at HP
I've attached what I'm going with. I've added the capability of getting
the file_operations from the cdev_map when necessary. The block device
code was also suffering from bit-rot as well, and so I put in a new
collector function that uses the bdev_map as well.
Thanks,
Dave
kernel.c dev.c symbols.c defs.h
--- crash-4.0-8.10/kernel.c 2009-06-04 17:13:29.000000000 -0400
+++ crash-4.0-8.10p1/kernel.c 2009-06-03 15:23:08.000000000 -0400
@@ -463,7 +463,26 @@
"char_device_struct", "fops");
MEMBER_OFFSET_INIT(char_device_struct_major,
"char_device_struct", "major");
- }
+ MEMBER_OFFSET_INIT(char_device_struct_baseminor,
+ "char_device_struct", "baseminor");
+ MEMBER_OFFSET_INIT(char_device_struct_cdev,
+ "char_device_struct", "cdev");
+ }
+
+ STRUCT_SIZE_INIT(cdev, "cdev");
+ if (VALID_STRUCT(cdev))
+ MEMBER_OFFSET_INIT(cdev_ops, "cdev", "ops");
+
+ STRUCT_SIZE_INIT(probe, "probe");
+ if (VALID_STRUCT(probe)) {
+ MEMBER_OFFSET_INIT(probe_next, "probe", "next");
+ MEMBER_OFFSET_INIT(probe_dev, "probe", "dev");
+ MEMBER_OFFSET_INIT(probe_data, "probe", "data");
+ }
+
+ STRUCT_SIZE_INIT(kobj_map, "kobj_map");
+ if (VALID_STRUCT(kobj_map))
+ MEMBER_OFFSET_INIT(kobj_map_probes, "kobj_map", "probes");
MEMBER_OFFSET_INIT(module_kallsyms_start, "module",
"kallsyms_start");
--- crash-4.0-8.10/dev.c 2009-06-04 17:13:29.000000000 -0400
+++ crash-4.0-8.10p1/dev.c 2009-06-05 10:06:46.000000000 -0400
@@ -20,6 +20,9 @@
static void dump_blkdevs(ulong);
static void dump_chrdevs(ulong);
static void dump_blkdevs_v2(ulong);
+static void dump_blkdevs_v3(ulong);
+static ulong search_cdev_map_probes(char *, int, int);
+static ulong search_bdev_map_probes(char *, int, int);
static void do_pci(void);
static void do_io(void);
static void do_resource_list(ulong, char *, int);
@@ -87,7 +90,7 @@
flags = 0;
- while ((c = getopt(argcnt, args, "pi")) != EOF) {
+ while ((c = getopt(argcnt, args, "pif")) != EOF) {
switch(c)
{
case 'i':
@@ -102,6 +105,10 @@
do_pci();
return;
+ case 'f':
+ flags = VERBOSE;
+ break;
+
default:
argerrs++;
break;
@@ -111,15 +118,19 @@
if (argerrs)
cmd_usage(pc->curcmd, SYNOPSIS);
- if (argcnt == 1) {
- dump_chrdevs(flags);
- fprintf(fp, "\n");
- dump_blkdevs(flags);
- }
+ dump_chrdevs(flags);
+ fprintf(fp, "\n");
+ dump_blkdevs(flags);
}
#define MAX_DEV (255)
+#define MINORBITS 20
+#define MINORMASK ((1U << MINORBITS) - 1)
+
+#define MAJOR(dev) ((unsigned int) ((dev) >> MINORBITS))
+#define MINOR(dev) ((unsigned int) ((dev) & MINORMASK))
+
char *chrdev_hdr = "CHRDEV NAME ";
char *blkdev_hdr = "BLKDEV NAME ";
@@ -139,8 +150,8 @@
} chrdevs[MAX_DEV], *cp;
ulong *cdp;
char *char_device_struct_buf;
- ulong next, savenext, name, fops;
- int major;
+ ulong next, savenext, name, fops, cdev;
+ int major, minor;
int name_typecode;
size_t name_size;
@@ -217,33 +228,57 @@
break;
}
- fops = ULONG(char_device_struct_buf +
- OFFSET(char_device_struct_fops));
major = INT(char_device_struct_buf +
OFFSET(char_device_struct_major));
+ minor = INT(char_device_struct_buf +
+ OFFSET(char_device_struct_baseminor));
+
+ fops = 0;
+ if (VALID_MEMBER(char_device_struct_cdev) &&
+ VALID_STRUCT(cdev)) {
+ cdev = ULONG(char_device_struct_buf +
+ OFFSET(char_device_struct_cdev));
+ if (cdev) {
+ addr = cdev + OFFSET(cdev_ops);
+ readmem(addr, KVADDR, &fops,
+ sizeof(void *),
+ "cdev ops", FAULT_ON_ERROR);
+ }
+ } else {
+ fops = ULONG(char_device_struct_buf +
+ OFFSET(char_device_struct_fops));
+ }
+
+ if (!fops)
+ fops = search_cdev_map_probes(buf, major, minor);
- fprintf(fp, " %3d ", major);
- fprintf(fp, "%-12s ", buf);
if (!fops) {
- sprintf(buf2, "%s%%%ds ",
- strlen("OPERATIONS") < VADDR_PRLEN ? " " : " ",
- VADDR_PRLEN);
- fprintf(fp, buf2, "(none)");
+ if (flags == VERBOSE) {
+ fprintf(fp, " %3d ", major);
+ fprintf(fp, "%-12s ", buf);
+ sprintf(buf2, "%s%%%ds ",
+ strlen("OPERATIONS") < VADDR_PRLEN ?
+ " " : " ", VADDR_PRLEN);
+ fprintf(fp, buf2, "(none)");
+ fprintf(fp, "\n");
+ }
} else {
- sprintf(buf2, "%s%%%dlx ",
- strlen("OPERATIONS") < VADDR_PRLEN ? " " : " ",
- VADDR_PRLEN);
- fprintf(fp, buf2, fops);
- value_to_symstr(fops, buf2, 0);
- if (strlen(buf2))
- fprintf(fp, "<%s>", buf2);
+ fprintf(fp, " %3d ", major);
+ fprintf(fp, "%-12s ", buf);
+ sprintf(buf2, "%s%%%dlx ",
+ strlen("OPERATIONS") < VADDR_PRLEN ? " " : " ",
+ VADDR_PRLEN);
+ fprintf(fp, buf2, fops);
+ value_to_symstr(fops, buf2, 0);
+ if (strlen(buf2))
+ fprintf(fp, "<%s>", buf2);
+ fprintf(fp, "\n");
}
- fprintf(fp, "\n");
if (CRASHDEBUG(1))
fprintf(fp,
- "%lx: major: %d name: %s next: %lx fops: %lx\n",
- *cdp, major, buf, next, fops);
+ "%lx: major: %d minor: %d name: %s next: %lx fops: %lx\n",
+ *cdp, major, minor, buf, next, fops);
while (next) {
readmem(savenext = next, KVADDR, char_device_struct_buf,
@@ -267,39 +302,114 @@
break;
}
- fops = ULONG(char_device_struct_buf +
- OFFSET(char_device_struct_fops));
major = INT(char_device_struct_buf +
OFFSET(char_device_struct_major));
+ minor = INT(char_device_struct_buf +
+ OFFSET(char_device_struct_baseminor));
+
+ fops = 0;
+ if (VALID_MEMBER(char_device_struct_cdev) &&
+ VALID_STRUCT(cdev)) {
+ cdev = ULONG(char_device_struct_buf +
+ OFFSET(char_device_struct_cdev));
+ if (cdev) {
+ addr = cdev + OFFSET(cdev_ops);
+ readmem(addr, KVADDR, &fops,
+ sizeof(void *),
+ "cdev ops", FAULT_ON_ERROR);
+ }
+ } else {
+ fops = ULONG(char_device_struct_buf +
+ OFFSET(char_device_struct_fops));
+ }
+
+ if (!fops)
+ fops = search_cdev_map_probes(buf, major, minor);
- fprintf(fp, " %3d ", major);
- fprintf(fp, "%-12s ", buf);
if (!fops) {
- sprintf(buf2, "%s%%%ds ",
- strlen("OPERATIONS") < VADDR_PRLEN ?
- " " : " ", VADDR_PRLEN);
- fprintf(fp, buf2, "(none)");
+ if (flags == VERBOSE) {
+ fprintf(fp, " %3d ", major);
+ fprintf(fp, "%-12s ", buf);
+ sprintf(buf2, "%s%%%ds ",
+ strlen("OPERATIONS") < VADDR_PRLEN ?
+ " " : " ", VADDR_PRLEN);
+ fprintf(fp, buf2, "(none)");
+ fprintf(fp, "\n");
+ }
} else {
- sprintf(buf2, "%s%%%dlx ",
- strlen("OPERATIONS") < VADDR_PRLEN ?
+ fprintf(fp, " %3d ", major);
+ fprintf(fp, "%-12s ", buf);
+ sprintf(buf2, "%s%%%dlx ",
+ strlen("OPERATIONS") < VADDR_PRLEN ?
" " : " ", VADDR_PRLEN);
- fprintf(fp, buf2, fops);
- value_to_symstr(fops, buf2, 0);
- if (strlen(buf2))
- fprintf(fp, "<%s>", buf2);
+ fprintf(fp, buf2, fops);
+ value_to_symstr(fops, buf2, 0);
+ if (strlen(buf2))
+ fprintf(fp, "<%s>", buf2);
+ fprintf(fp, "\n");
}
- fprintf(fp, "\n");
if (CRASHDEBUG(1))
fprintf(fp,
- "%lx: major: %d name: %s next: %lx fops: %lx\n",
- savenext, major, buf, next, fops);
+ "%lx: major: %d minor: %d name: %s next: %lx fops: %lx\n",
+ savenext, major, minor, buf, next, fops);
}
}
FREEBUF(char_device_struct_buf);
}
+/*
+ * Search for a major/minor match by following the list headed
+ * by the kobj_map.probes[major] array entry. The "data" member
+ * points to a cdev structure containing the file_operations
+ * pointer.
+ */
+static ulong
+search_cdev_map_probes(char *name, int major, int minor)
+{
+ char *probe_buf;
+ ulong probes[MAX_DEV];
+ ulong cdev_map, addr, next, ops, probe_data;
+ uint probe_dev;
+
+ if (kernel_symbol_exists("cdev_map"))
+ get_symbol_data("cdev_map", sizeof(ulong), &cdev_map);
+ else
+ return 0;
+
+ addr = cdev_map + OFFSET(kobj_map_probes);
+ if (!readmem(addr, KVADDR, &probes[0], sizeof(void *) * MAX_DEV,
+ "cdev_map.probes[]", QUIET|RETURN_ON_ERROR))
+ return 0;
+
+ ops = 0;
+ probe_buf = GETBUF(SIZE(probe));
+ next = probes[major];
+
+ while (next) {
+ if (!readmem(next, KVADDR, probe_buf, SIZE(probe),
+ "struct probe", QUIET|RETURN_ON_ERROR))
+ break;
+
+ probe_dev = UINT(probe_buf + OFFSET(probe_dev));
+
+ if ((MAJOR(probe_dev) == major) &&
+ (MINOR(probe_dev) == minor)) {
+ probe_data = ULONG(probe_buf + OFFSET(probe_data));
+ addr = probe_data + OFFSET(cdev_ops);
+ if (!readmem(addr, KVADDR, &ops, sizeof(void *),
+ "cdev ops", QUIET|RETURN_ON_ERROR))
+ ops = 0;
+ break;
+ }
+
+ next = ULONG(probe_buf + OFFSET(probe_next));
+ }
+
+ FREEBUF(probe_buf);
+ return ops;
+}
/*
* Dump the block device data.
@@ -315,6 +425,12 @@
ulong ops;
} blkdevs[MAX_DEV], *bp;
+ if (kernel_symbol_exists("major_names") &&
+ kernel_symbol_exists("bdev_map")) {
+ dump_blkdevs_v3(flags);
+ return;
+ }
+
if (symbol_exists("all_bdevs")) {
dump_blkdevs_v2(flags);
return;
@@ -524,6 +640,131 @@
FREEBUF(blk_major_name_buf);
}
+static void
+dump_blkdevs_v3(ulong flags)
+{
+ int i, len;
+ ulong blk_major_name;
+ char *blk_major_name_buf;
+ char buf[BUFSIZE];
+ char buf2[BUFSIZE];
+ uint major;
+ ulong addr, next, fops;
+
+ if (!(len = get_array_length("major_names", NULL, 0)))
+ len = MAX_DEV;
+
+ fprintf(fp, "%s%s\n", blkdev_hdr,
+ mkstring(buf, VADDR_PRLEN, CENTER, "OPERATIONS"));
+
+ blk_major_name_buf = GETBUF(SIZE(blk_major_name));
+
+ for (i = 0; i < len; i++) {
+ addr = symbol_value("major_names") + (i * sizeof(void *));
+ readmem(addr, KVADDR, &blk_major_name, sizeof(void *),
+ "major_names[] entry", FAULT_ON_ERROR);
+
+ if (!blk_major_name)
+ continue;
+
+ readmem(blk_major_name, KVADDR, blk_major_name_buf,
+ SIZE(blk_major_name), "blk_major_name", FAULT_ON_ERROR);
+
+ major = UINT(blk_major_name_buf +
+ OFFSET(blk_major_name_major));
+ buf[0] = NULLCHAR;
+ strncpy(buf, blk_major_name_buf +
+ OFFSET(blk_major_name_name), 16);
+ next = ULONG(blk_major_name_buf +
+ OFFSET(blk_major_name_next));
+
+ if (major != i)
+ continue;
+
+ fops = search_bdev_map_probes(buf, major, UNUSED);
+
+ if (CRASHDEBUG(1))
+ fprintf(fp, "[%lx] block major: %d name: %s\n",
+ blk_major_name, major, buf);
+
+ if (!fops) {
+ if (flags == VERBOSE) {
+ fprintf(fp, " %3d ", major);
+ fprintf(fp, "%-12s ",
+ strlen(buf) ? buf : "(unknown)");
+ sprintf(buf2, "%s%%%ds ",
+ strlen("OPERATIONS") < VADDR_PRLEN ?
+ " " : " ", VADDR_PRLEN);
+ fprintf(fp, buf2, "(none)");
+ fprintf(fp, "\n");
+ }
+ continue;
+ }
+
+ fprintf(fp, " %3d ", major);
+ fprintf(fp, "%-12s ", strlen(buf) ? buf : "(unknown)");
+ sprintf(buf, "%s%%%dlx ",
+ strlen("OPERATIONS") < VADDR_PRLEN ? " " : " ",
+ VADDR_PRLEN);
+ fprintf(fp, buf, fops);
+ value_to_symstr(fops, buf, 0);
+ if (strlen(buf))
+ fprintf(fp, "<%s>", buf);
+ fprintf(fp, "\n");
+ }
+}
+
+static ulong
+search_bdev_map_probes(char *name, int major, int minor)
+{
+ char *probe_buf, *gendisk_buf;
+ ulong probes[MAX_DEV];
+ ulong bdev_map, addr, next, probe_data, fops;
+ uint probe_dev;
+
+ get_symbol_data("bdev_map", sizeof(ulong), &bdev_map);
+
+ addr = bdev_map + OFFSET(kobj_map_probes);
+ if (!readmem(addr, KVADDR, &probes[0], sizeof(void *) * MAX_DEV,
+ "bdev_map.probes[]", QUIET|RETURN_ON_ERROR))
+ return 0;
+
+ probe_buf = GETBUF(SIZE(probe));
+ gendisk_buf = GETBUF(SIZE(gendisk));
+
+ fops = 0;
+
+ for (next = probes[major]; next;
+ next = ULONG(probe_buf + OFFSET(probe_next))) {
+
+ if (!readmem(next, KVADDR, probe_buf, SIZE(probe),
+ "struct probe", QUIET|RETURN_ON_ERROR))
+ break;
+
+ probe_data = ULONG(probe_buf + OFFSET(probe_data));
+ if (!probe_data)
+ continue;
+
+ probe_dev = UINT(probe_buf + OFFSET(probe_dev));
+ if (MAJOR(probe_dev) != major)
+ continue;
+
+ if (!readmem(probe_data, KVADDR, gendisk_buf,
+ SIZE(gendisk), "gendisk buffer",
+ QUIET|RETURN_ON_ERROR))
+ break;
+
+ fops = ULONG(gendisk_buf + OFFSET(gendisk_fops));
+
+ if (fops)
+ break;
+ }
+
+ FREEBUF(probe_buf);
+ FREEBUF(gendisk_buf);
+ return fops;
+}
+
void
dump_dev_table(void)
{
--- crash-4.0-8.10/symbols.c 2009-06-04 17:13:28.000000000 -0400
+++ crash-4.0-8.10p1/symbols.c 2009-06-03 15:21:50.000000000 -0400
@@ -7024,6 +7024,21 @@
OFFSET(char_device_struct_fops));
fprintf(fp, " char_device_struct_major: %ld\n",
OFFSET(char_device_struct_major));
+ fprintf(fp, " char_device_struct_baseminor: %ld\n",
+ OFFSET(char_device_struct_baseminor));
+ fprintf(fp, " char_device_struct_cdev: %ld\n",
+ OFFSET(char_device_struct_cdev));
+
+ fprintf(fp, " cdev_ops: %ld\n", OFFSET(cdev_ops));
+
+ fprintf(fp, " probe_next: %ld\n",
+ OFFSET(probe_next));
+ fprintf(fp, " probe_dev: %ld\n",
+ OFFSET(probe_dev));
+ fprintf(fp, " probe_data: %ld\n",
+ OFFSET(probe_data));
+ fprintf(fp, " kobj_map_probes: %ld\n",
+ OFFSET(kobj_map_probes));
fprintf(fp, " blk_major_name_next: %ld\n",
OFFSET(blk_major_name_next));
@@ -7266,6 +7281,12 @@
SIZE(pcpu_info));
fprintf(fp, " vcpu_struct: %ld\n",
SIZE(vcpu_struct));
+ fprintf(fp, " cdev: %ld\n",
+ SIZE(cdev));
+ fprintf(fp, " probe: %ld\n",
+ SIZE(probe));
+ fprintf(fp, " kobj_map: %ld\n",
+ SIZE(kobj_map));
fprintf(fp, "\n array_table:\n");
/*
--- crash-4.0-8.10/defs.h 2009-06-04 17:13:29.000000000 -0400
+++ crash-4.0-8.10p1/defs.h 2009-06-05 09:50:19.000000000 -0400
@@ -1466,6 +1466,13 @@
long sched_info_last_arrival;
long page_objects;
long kmem_cache_oo;
+ long char_device_struct_cdev;
+ long char_device_struct_baseminor;
+ long cdev_ops;
+ long probe_next;
+ long probe_dev;
+ long probe_data;
+ long kobj_map_probes;
};
struct size_table { /* stash of commonly-used sizes */
@@ -1571,6 +1578,9 @@
long cfs_rq;
long pcpu_info;
long vcpu_struct;
+ long cdev;
+ long probe;
+ long kobj_map;
};
struct array_table {
--
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