We are creating a vmcore using kexec on a Linux 6.15 RISC-V system and analyzing it with the crash tool on the host.
This workflow used to work on Linux 6.14 but is now broken in 6.15.

The issue is caused by a change in the kernel:
In Linux 6.15, certain memblock sections are now marked as Reserved in /proc/iomem.
The kexec tool excludes all Reserved regions when generating the vmcore, so these sections are missing from the dump.

However, the kernel still uses addresses in these regions—for example, for IRQ pointers.
Since the crash tool needs access to these memory areas to function correctly, their exclusion breaks the analysis.


Pnina Feder (1):
  riscv: Change memblock reserved name to be recognized on kexec

 arch/riscv/kernel/setup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.43.0

Pnina!

Pnina Feder <pnina.feder@mobileye.com> writes:

> We are creating a vmcore using kexec on a Linux 6.15 RISC-V system and
> analyzing it with the crash tool on the host. This workflow used to
> work on Linux 6.14 but is now broken in 6.15.

Thanks for reporting this!

> The issue is caused by a change in the kernel:
> In Linux 6.15, certain memblock sections are now marked as Reserved in
> /proc/iomem. The kexec tool excludes all Reserved regions when
> generating the vmcore, so these sections are missing from the dump.

How are you collecting the /proc/vmcore file? A full set of commands
would be helpful.

> However, the kernel still uses addresses in these regions—for example,
> for IRQ pointers. Since the crash tool needs access to these memory
> areas to function correctly, their exclusion breaks the analysis.

Wdym with "IRQ pointers"? Also, what version (sha1) of crash are you
using?


Thanks!
Björn