On 2023/05/10 10:44, HAGIO KAZUHITO(萩尾 一仁) wrote:
On 2023/05/10 4:33, Luiz Capitulino wrote:
On 2023-05-09 03:32, HAGIO KAZUHITO(萩尾 一仁) wrote:
On 2023/05/02 3:41, Luiz Capitulino wrote:
Hi all,
I'm trying to run latest crash (HEAD 2505a65ff54) against kernel
4.14.314 but I'm getting the error below on startup.
Is this a known issue? If not, any suggestions on how to debug it?
hmm, I tried the kernel version, but could not reproduce it.
crash> sys
KERNEL: /lib/modules/4.14.314/build/vmlinux
DUMPFILE: /proc/kcore
CPUS: 4
DATE: Tue May 9 16:16:14 JST 2023
UPTIME: 00:07:02
LOAD AVERAGE: 0.07, 0.12, 0.07
TASKS: 174
NODENAME: rhel78b
RELEASE: 4.14.314
VERSION: #1 SMP Tue May 9 15:28:59 JST 2023
MACHINE: x86_64 (3408 Mhz)
MEMORY: 4 GB
Could you upload a startup log with "crash -d 8" option?
I'm attaching a file with this information, thanks a lot for looking
into this.
Thanks.
-----
module: ffffffffa00f8f80
<readmem: ffffffffa00f8f80, KVADDR, "module struct", 896, (ROE|Q), 122f800>
<readmem: 200e000, PHYSADDR, "pud page", 4096, (FOE), 1c95e00>
<read_proc_kcore: addr: 200e000 paddr: 200e000 cnt: 4096>
crash: seek error: physical address: 200e000 type: "pud page"
-----
It seems that the virt to phys conversion for ffffffffa00f8f80 fails
because the file offset of the pud page is not found in /proc/kcore.
According to read_proc_kcore(), it does
1. p2v for 200e000 i.e. phys:200e000 --> virt:???
2. search /proc/kcore pt_loads for the corresponding file offset to the
virtual address. (as pc->curcmd_flags does not have MEMTYPE_KVADDR.)
3. read the file offset.
so, what is the converted virtual address? For example,
--- a/netdump.c
+++ b/netdump.c
@@ -4362,6 +4362,8 @@ read_proc_kcore(int fd, void *bufptr, int cnt, ulong addr, physaddr_t paddr)
else
kvaddr = PTOV((ulong)paddr);
+ fprintf(fp, "kvaddr: %lx\n", kvaddr);
+
offset = UNINITIALIZED;
readcnt = cnt;
Ah, probably got it.
The PTOV() above is defined like this:
#define PTOV(X) ((unsigned long)(X)+(machdep->kvbase))
Your kernel has the following pt_load information, probably it's out of
these vaddr ranges?
offset vaddr end paddr end size
7fffff604000 ffffffffff600000-ffffffffff601000 ffffffffffffffff- 0 (1000)
7fff81004000 ffffffff81000000-ffffffff8377f000 1000000- 377f000 (277f000)
490000004000 ffffc90000000000-ffffe90000000000 ffffffffffffffff- 0 (1fffffffffff)
7fffa0004000 ffffffffa0000000-ffffffffff000000 ffffffffffffffff- 0 (5f000000)
88000005000 ffff888000001000-ffff88800009f000 1000- 9f000 (9e000)
6a0000004000 ffffea0000000000-ffffea0000003000 ffffffffffffffff- 0 (3000)
88000104000 ffff888000100000-ffff8880bffe8000 100000- bffe8000 (bfee8000)
6a0000008000 ffffea0000004000-ffffea0003000000 ffffffffffffffff- 0 (2ffc000)
88100004000 ffff888100000000-ffff888fff000000 100000000-fff000000 (eff000000)
6a0004004000 ffffea0004000000-ffffea003ffc0000 ffffffffffffffff- 0 (3bfc0000)
Your kernel looks configured without CONFIG_RANDOMIZE_BASE. For such
kernels, a hard-coded value is used for PAGE_OFFSET and kvbase. And
I found that Linux 4.14.84 and later has the recent PAGE_OFFSET.
case POST_GDB:
if (!(machdep->flags & RANDOMIZED) &&
((THIS_KERNEL_VERSION >= LINUX(4,19,5)) ||
((THIS_KERNEL_VERSION >= LINUX(4,14,84)) &&
(THIS_KERNEL_VERSION < LINUX(4,15,0))))) {
machdep->machspec->page_offset = machdep->flags & VM_5LEVEL ?
PAGE_OFFSET_5LEVEL_4_20 : PAGE_OFFSET_4LEVEL_4_20;
machdep->kvbase = machdep->machspec->page_offset;
#define PAGE_OFFSET_4LEVEL_4_20 0xffff888000000000
But, the THIS_KERNEL_VERSION and LINUX() macros are defined like this:
#define THIS_KERNEL_VERSION ((kt->kernel_version[0] << 16) + \
(kt->kernel_version[1] << 8) + \
(kt->kernel_version[2]))
#define LINUX(x,y,z) (((uint)(x) << 16) + ((uint)(y) << 8) + (uint)(z))
So (THIS_KERNEL_VERSION < LINUX(4,15,0)) is false on Linux 4.14.256 and
later, and the old PAGE_OFFSET will be used.
So does this patch work well?
