2:24 a.m.
Hi Chengen,
thank you for the patch.
On 2023/11/09 11:54, Chengen Du wrote:
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 | 61 +++++++++++++++++++++++++++++++++++-------------------
2 files changed, 41 insertions(+), 21 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..0103221 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)
@@ -2764,7 +2766,10 @@ zram_init(void)
long zram_flag_shift;
MEMBER_OFFSET_INIT(zram_mempoll, "zram", "mem_pool");
- MEMBER_OFFSET_INIT(zram_compressor, "zram", "compressor");
+ if (THIS_KERNEL_VERSION >= LINUX(6, 2, 0))
+ MEMBER_OFFSET_INIT(zram_comp_algs, "zram", "comp_algs");
+ else
+ MEMBER_OFFSET_INIT(zram_compressor, "zram", "compressor");
Kernel patches can be backported to kernels older than 6.2.0, please
don't use the kernel version if possible. So, for example:
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 +2787,8 @@ 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 +2987,17 @@ 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 = (THIS_KERNEL_VERSION >= LINUX(6, 2, 0))
+ ? INVALID_MEMBER(zram_comp_algs) : INVALID_MEMBER(zram_compressor);
Same as above, for example, this works?
if (INVALID_MEMBER(zram_comp_algs) && INVALID_MEMBER(zram_compressor))
+ 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 = (THIS_KERNEL_VERSION >= LINUX(6, 2, 0))
+ ? INVALID_MEMBER(zram_comp_algs) : INVALID_MEMBER(zram_compressor);
+ if (comp_alg_unavail) {
+ error(WARNING, "some pages are swapped out to zram. "
+ "please run mod -s zram.\n");
return 0;
}
}
@@ -2997,8 +3008,29 @@ 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 (THIS_KERNEL_VERSION >= LINUX(6, 2, 0)) {
Same as above.
Thanks,
Kazu
> + 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));
> + } else {
> + readmem(zram + OFFSET(zram_compressor), KVADDR, name, sizeof(name),
> + "zram compressor", FAULT_ON_ERROR);
> + }
> if (STREQ(name, "lzo")) {
> #ifdef LZO
> if (!(dd->flags & LZO_SUPPORTED)) {
> @@ -3019,12 +3051,6 @@ 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 +3060,8 @@ 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());