9:45 p.m.
A kernel commit 7ac07a26dea7 (zram: preparation for multi-zcomp support)
in Linux replaces "compressor" with "comp_algs" in the zram struct.
If not fixed, the issue triggers the following error:
rd: WARNING: Some pages are swapped out to zram. Please run mod -s zram.
rd: invalid user virtual address: ffff7d23f010 type: "64-bit UVADDR"
Signed-off-by: Chengen Du <chengen.du(a)canonical.com>
---
defs.h | 1 +
diskdump.c | 56 +++++++++++++++++++++++++++++++++++-------------------
2 files changed, 37 insertions(+), 20 deletions(-)
diff --git a/defs.h b/defs.h
index 788f63a..2cae5b6 100644
--- a/defs.h
+++ b/defs.h
@@ -2227,6 +2227,7 @@ struct offset_table { /* stash of commonly-used
offsets */
long module_memory_size;
long irq_data_irq;
long zspage_huge;
+ long zram_comp_algs;
};
struct size_table { /* stash of commonly-used sizes */
diff --git a/diskdump.c b/diskdump.c
index 0fe46f4..d7e4380 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -2757,6 +2757,8 @@ diskdump_device_dump_info(FILE *ofp)
static ulong ZRAM_FLAG_SHIFT;
static ulong ZRAM_FLAG_SAME_BIT;
+static ulong ZRAM_COMP_PRIORITY_BIT1;
+static ulong ZRAM_COMP_PRIORITY_MASK;
static void
zram_init(void)
@@ -2765,6 +2767,8 @@ zram_init(void)
MEMBER_OFFSET_INIT(zram_mempoll, "zram", "mem_pool");
MEMBER_OFFSET_INIT(zram_compressor, "zram", "compressor");
+ if (INVALID_MEMBER(zram_compressor))
+ MEMBER_OFFSET_INIT(zram_comp_algs, "zram", "comp_algs");
MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "flags");
if (INVALID_MEMBER(zram_table_flag))
MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "value");
@@ -2782,6 +2786,8 @@ zram_init(void)
ZRAM_FLAG_SHIFT = 1 << zram_flag_shift;
ZRAM_FLAG_SAME_BIT = 1 << (zram_flag_shift+1);
+ ZRAM_COMP_PRIORITY_BIT1 = ZRAM_FLAG_SHIFT + 7;
+ ZRAM_COMP_PRIORITY_MASK = 0x3;
if (CRASHDEBUG(1))
fprintf(fp, "zram_flag_shift: %ld\n", zram_flag_shift);
@@ -2980,13 +2986,15 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong
len, ulonglong
unsigned char *outbuf = NULL;
ulong zram, zram_table_entry, sector, index, entry, flags, size,
outsize, off;
+ int comp_alg_unavail;
- if (INVALID_MEMBER(zram_compressor)) {
+ comp_alg_unavail = INVALID_MEMBER(zram_compressor) &&
INVALID_MEMBER(zram_comp_algs);
+ if (comp_alg_unavail) {
zram_init();
- if (INVALID_MEMBER(zram_compressor)) {
- error(WARNING,
- "Some pages are swapped out to zram. "
- "Please run mod -s zram.\n");
+ comp_alg_unavail = INVALID_MEMBER(zram_compressor) &&
INVALID_MEMBER(zram_comp_algs);
+ if (comp_alg_unavail) {
+ error(WARNING, "some pages are swapped out to zram. "
+ "please run mod -s zram.\n");
return 0;
}
}
@@ -2997,8 +3005,29 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong
len, ulonglong
if (!get_disk_name_private_data(pte_val, vaddr, NULL, &zram))
return 0;
- readmem(zram + OFFSET(zram_compressor), KVADDR, name,
- sizeof(name), "zram compressor", FAULT_ON_ERROR);
+ if (THIS_KERNEL_VERSION >= LINUX(2, 6, 0)) {
+ swp_offset = (ulonglong)__swp_offset(pte_val);
+ } else {
+ swp_offset = (ulonglong)SWP_OFFSET(pte_val);
+ }
+
+ sector = swp_offset << (PAGESHIFT() - 9);
+ index = sector >> SECTORS_PER_PAGE_SHIFT;
+ readmem(zram, KVADDR, &zram_table_entry,
+ sizeof(void *), "zram_table_entry", FAULT_ON_ERROR);
+ zram_table_entry += (index * SIZE(zram_table_entry));
+ readmem(zram_table_entry + OFFSET(zram_table_flag), KVADDR, &flags,
+ sizeof(void *), "zram_table_flag", FAULT_ON_ERROR);
+ if (VALID_MEMBER(zram_compressor)) {
+ readmem(zram + OFFSET(zram_compressor), KVADDR, name, sizeof(name),
+ "zram compressor", FAULT_ON_ERROR);
+ } else {
+ ulong comp_alg_addr;
+ uint32_t prio = (flags >> ZRAM_COMP_PRIORITY_BIT1) &
ZRAM_COMP_PRIORITY_MASK;
+ readmem(zram + OFFSET(zram_comp_algs) + sizeof(const char *) * prio, KVADDR,
+ &comp_alg_addr, sizeof(comp_alg_addr), "zram comp_algs",
FAULT_ON_ERROR);
+ read_string(comp_alg_addr, name, sizeof(name));
+ }
if (STREQ(name, "lzo")) {
#ifdef LZO
if (!(dd->flags & LZO_SUPPORTED)) {
@@ -3019,12 +3048,6 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong
len, ulonglong
return 0;
}
- if (THIS_KERNEL_VERSION >= LINUX(2, 6, 0)) {
- swp_offset = (ulonglong)__swp_offset(pte_val);
- } else {
- swp_offset = (ulonglong)SWP_OFFSET(pte_val);
- }
-
zram_buf = (unsigned char *)GETBUF(PAGESIZE());
/* lookup page from swap cache */
off = PAGEOFFSET(vaddr);
@@ -3034,15 +3057,8 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong
len, ulonglong
goto out;
}
- sector = swp_offset << (PAGESHIFT() - 9);
- index = sector >> SECTORS_PER_PAGE_SHIFT;
- readmem(zram, KVADDR, &zram_table_entry,
- sizeof(void *), "zram_table_entry", FAULT_ON_ERROR);
- zram_table_entry += (index * SIZE(zram_table_entry));
readmem(zram_table_entry, KVADDR, &entry,
sizeof(void *), "entry of table", FAULT_ON_ERROR);
- readmem(zram_table_entry + OFFSET(zram_table_flag), KVADDR, &flags,
- sizeof(void *), "zram_table_flag", FAULT_ON_ERROR);
if (!entry || (flags & ZRAM_FLAG_SAME_BIT)) {
int count;
ulong *same_buf = (ulong *)GETBUF(PAGESIZE());
--
2.40.1