linux-stable.git/kernel/crash_core.c, branch v6.7.8

kdump: defer the insertion of crashkernel resources

2024-02-01T00:21:02+00:00

commit 4a693ce65b186fddc1a73621bd6f941e6e3eca21 upstream.

In /proc/iomem, sub-regions should be inserted after their parent,
otherwise the insertion of parent resource fails.  But after generic
crashkernel reservation applied, in both RISC-V and ARM64 (LoongArch will
also use generic reservation later on), crashkernel resources are inserted
before their parent, which causes the parent disappear in /proc/iomem.  So
we defer the insertion of crashkernel resources to an early_initcall().

1, Without 'crashkernel' parameter:

 100d0100-100d01ff : LOON0001:00
   100d0100-100d01ff : LOON0001:00 LOON0001:00
 100e0000-100e0bff : LOON0002:00
   100e0000-100e0bff : LOON0002:00 LOON0002:00
 1fe001e0-1fe001e7 : serial
 90400000-fa17ffff : System RAM
   f6220000-f622ffff : Reserved
   f9ee0000-f9ee3fff : Reserved
   fa120000-fa17ffff : Reserved
 fa190000-fe0bffff : System RAM
   fa190000-fa1bffff : Reserved
 fe4e0000-47fffffff : System RAM
   43c000000-441ffffff : Reserved
   47ff98000-47ffa3fff : Reserved
   47ffa4000-47ffa7fff : Reserved
   47ffa8000-47ffabfff : Reserved
   47ffac000-47ffaffff : Reserved
   47ffb0000-47ffb3fff : Reserved

2, With 'crashkernel' parameter, before this patch:

 100d0100-100d01ff : LOON0001:00
   100d0100-100d01ff : LOON0001:00 LOON0001:00
 100e0000-100e0bff : LOON0002:00
   100e0000-100e0bff : LOON0002:00 LOON0002:00
 1fe001e0-1fe001e7 : serial
 e6200000-f61fffff : Crash kernel
 fa190000-fe0bffff : System RAM
   fa190000-fa1bffff : Reserved
 fe4e0000-47fffffff : System RAM
   43c000000-441ffffff : Reserved
   47ff98000-47ffa3fff : Reserved
   47ffa4000-47ffa7fff : Reserved
   47ffa8000-47ffabfff : Reserved
   47ffac000-47ffaffff : Reserved
   47ffb0000-47ffb3fff : Reserved

3, With 'crashkernel' parameter, after this patch:

 100d0100-100d01ff : LOON0001:00
   100d0100-100d01ff : LOON0001:00 LOON0001:00
 100e0000-100e0bff : LOON0002:00
   100e0000-100e0bff : LOON0002:00 LOON0002:00
 1fe001e0-1fe001e7 : serial
 90400000-fa17ffff : System RAM
   e6200000-f61fffff : Crash kernel
   f6220000-f622ffff : Reserved
   f9ee0000-f9ee3fff : Reserved
   fa120000-fa17ffff : Reserved
 fa190000-fe0bffff : System RAM
   fa190000-fa1bffff : Reserved
 fe4e0000-47fffffff : System RAM
   43c000000-441ffffff : Reserved
   47ff98000-47ffa3fff : Reserved
   47ffa4000-47ffa7fff : Reserved
   47ffa8000-47ffabfff : Reserved
   47ffac000-47ffaffff : Reserved
   47ffb0000-47ffb3fff : Reserved

Link: https://lkml.kernel.org/r/20231229080213.2622204-1-chenhuacai@loongson.cn
Signed-off-by: Huacai Chen 
Fixes: 0ab97169aa05 ("crash_core: add generic function to do reservation")
Cc: Baoquan He 
Cc: Zhen Lei 
Cc: 	[6.6+]
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

crash_core: fix the check for whether crashkernel is from high memory

2023-12-13T01:20:18+00:00

If crash_base is equal to CRASH_ADDR_LOW_MAX, it also indicates that
the crashkernel memory is allocated from high memory. However, the
current check only considers the case where crash_base is greater than
CRASH_ADDR_LOW_MAX. Fix it.

The runtime effects is that crashkernel high memory is successfully
reserved, whereas the crashkernel low memory is bypassed in this case,
then kdump kernel bootup will fail because of no low memory under 4G.

This patch also includes some minor cleanups.

Link: https://lkml.kernel.org/r/20231209141438.77233-1-ytcoode@gmail.com
Fixes: 0ab97169aa05 ("crash_core: add generic function to do reservation")
Signed-off-by: Yuntao Wang 
Cc: Baoquan He 
Cc: Dave Young 
Cc: Vivek Goyal 
Cc: Zhen Lei 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton

crash_core.c: remove unneeded functions

2023-10-04T17:41:58+00:00

So far, nobody calls functions parse_crashkernel_high() and
parse_crashkernel_low(), remove both of them.

Link: https://lkml.kernel.org/r/20230914033142.676708-10-bhe@redhat.com
Signed-off-by: Baoquan He 
Reviewed-by: Zhen Lei 
Cc: Catalin Marinas 
Cc: Chen Jiahao 
Signed-off-by: Andrew Morton

crash_core: move crashk_*res definition into crash_core.c

2023-10-04T17:41:58+00:00

Both crashk_res and crashk_low_res are used to mark the reserved
crashkernel regions in iomem_resource tree.  And later the generic
crashkernel resrvation will be added into crash_core.c.  So move
crashk_res and crashk_low_res definition into crash_core.c to avoid
compiling error if CONFIG_CRASH_CORE=on while CONFIG_KEXEC_CORE is unset.

Meanwhile include  in  if generic
reservation is needed.  In that case,  need be added by
ARCH.  In asm/crash_core.h, ARCH can provide its own macro definitions to
override macros in  if needed.  Wrap the including
into CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION ifdeffery scope to
avoid compiling error in other ARCH-es which don't take the generic
reservation way yet.

Link: https://lkml.kernel.org/r/20230914033142.676708-6-bhe@redhat.com
Signed-off-by: Baoquan He 
Reviewed-by: Zhen Lei 
Cc: Catalin Marinas 
Cc: Chen Jiahao 
Signed-off-by: Andrew Morton

crash_core: add generic function to do reservation

2023-10-04T17:41:58+00:00

In architecture like x86_64, arm64 and riscv, they have vast virtual
address space and usually have huge physical memory RAM.  Their
crashkernel reservation doesn't have to be limited under 4G RAM, but can
be extended to the whole physical memory via crashkernel=,high support.

Now add function reserve_crashkernel_generic() to reserve crashkernel
memory if users specify any case of kernel pamameters, like
crashkernel=xM[@offset] or crashkernel=,high|low.

This is preparation to simplify code of crashkernel=,high support in
architecutures.

Link: https://lkml.kernel.org/r/20230914033142.676708-5-bhe@redhat.com
Signed-off-by: Baoquan He 
Reviewed-by: Zhen Lei 
Cc: Catalin Marinas 
Cc: Chen Jiahao 
Signed-off-by: Andrew Morton

crash_core: change parse_crashkernel() to support crashkernel=,high|low parsing

2023-10-04T17:41:58+00:00

Now parse_crashkernel() is a real entry point for all kinds of crahskernel
parsing on any architecture.

And wrap the crahskernel=,high|low handling inside
CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION ifdeffery scope.

Link: https://lkml.kernel.org/r/20230914033142.676708-4-bhe@redhat.com
Signed-off-by: Baoquan He 
Reviewed-by: Zhen Lei 
Cc: Catalin Marinas 
Cc: Chen Jiahao 
Signed-off-by: Andrew Morton

crash_core: change the prototype of function parse_crashkernel()

2023-10-04T17:41:58+00:00

Add two parameters 'low_size' and 'high' to function parse_crashkernel(),
later crashkernel=,high|low parsing will be added.  Make adjustments in
all call sites of parse_crashkernel() in arch.

Link: https://lkml.kernel.org/r/20230914033142.676708-3-bhe@redhat.com
Signed-off-by: Baoquan He 
Reviewed-by: Zhen Lei 
Cc: Catalin Marinas 
Cc: Chen Jiahao 
Signed-off-by: Andrew Morton

crash_core.c: remove unnecessary parameter of function

2023-10-04T17:41:58+00:00

Patch series "kdump: use generic functions to simplify crashkernel
reservation in arch", v3.

In the current arm64, crashkernel=,high support has been finished after
several rounds of posting and careful reviewing.  The code in arm64 which
parses crashkernel kernel parameters firstly, then reserve memory can be a
good example for other ARCH to refer to.

Whereas in x86_64, the code mixing crashkernel parameter parsing and
memory reserving is twisted, and looks messy.  Refactoring the code to
make it more readable maintainable is necessary.

Here, firstly abstract the crashkernel parameter parsing code into
parse_crashkernel() to make it be able to parse crashkernel=,high|low. 
Then abstract the crashkernel memory reserving code into a generic
function reserve_crashkernel_generic().  Finally, in ARCH which
crashkernel=,high support is needed, a simple arch_reserve_crashkernel()
can be added to call above two functions.  This can remove the duplicated
implmentation code in each ARCH, like arm64, x86_64 and riscv.

crashkernel=512M,high
crashkernel=512M,high crashkernel=256M,low
crashkernel=512M,high crashkernel=0M,low
crashkernel=0M,high crashkernel=256M,low
crashkernel=512M
crashkernel=512M@0x4f000000
crashkernel=1G-4G:256M,4G-64G:320M,64G-:576M
crashkernel=0M


This patch (of 9):

In all call sites of __parse_crashkernel(), the parameter 'name' is
hardcoded as "crashkernel=".  So remove the unnecessary parameter 'name',
add local varibale 'name' inside __parse_crashkernel() instead.

Link: https://lkml.kernel.org/r/20230914033142.676708-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20230914033142.676708-2-bhe@redhat.com
Signed-off-by: Baoquan He 
Reviewed-by: Zhen Lei 
Cc: Catalin Marinas 
Cc: Chen Jiahao 
Cc: Zhen Lei 
Signed-off-by: Andrew Morton

Crash: add lock to serialize crash hotplug handling

2023-09-30T00:20:48+00:00

Eric reported that handling corresponding crash hotplug event can be
failed easily when many memory hotplug event are notified in a short
period.  They failed because failing to take __kexec_lock.

=======
[   78.714569] Fallback order for Node 0: 0
[   78.714575] Built 1 zonelists, mobility grouping on.  Total pages: 1817886
[   78.717133] Policy zone: Normal
[   78.724423] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
[   78.727207] crash hp: kexec_trylock() failed, elfcorehdr may be inaccurate
[   80.056643] PEFILE: Unsigned PE binary
=======

The memory hotplug events are notified very quickly and very many, while
the handling of crash hotplug is much slower relatively.  So the atomic
variable __kexec_lock and kexec_trylock() can't guarantee the
serialization of crash hotplug handling.

Here, add a new mutex lock __crash_hotplug_lock to serialize crash hotplug
handling specifically.  This doesn't impact the usage of __kexec_lock.

Link: https://lkml.kernel.org/r/20230926120905.392903-1-bhe@redhat.com
Fixes: 247262756121 ("crash: add generic infrastructure for crash hotplug support")
Signed-off-by: Baoquan He 
Tested-by: Eric DeVolder 
Reviewed-by: Eric DeVolder 
Reviewed-by: Valentin Schneider 
Cc: Sourabh Jain 
Cc: 
Signed-off-by: Andrew Morton

Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-08-29T21:53:51+00:00

Pull non-MM updates from Andrew Morton:

 - An extensive rework of kexec and crash Kconfig from Eric DeVolder
   ("refactor Kconfig to consolidate KEXEC and CRASH options")

 - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
   couple of macros to args.h")

 - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
   commands")

 - vsprintf inclusion rationalization from Andy Shevchenko
   ("lib/vsprintf: Rework header inclusions")

 - Switch the handling of kdump from a udev scheme to in-kernel
   handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
   hot un/plug")

 - Many singleton patches to various parts of the tree

* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
  document while_each_thread(), change first_tid() to use for_each_thread()
  drivers/char/mem.c: shrink character device's devlist[] array
  x86/crash: optimize CPU changes
  crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
  crash: hotplug support for kexec_load()
  x86/crash: add x86 crash hotplug support
  crash: memory and CPU hotplug sysfs attributes
  kexec: exclude elfcorehdr from the segment digest
  crash: add generic infrastructure for crash hotplug support
  crash: move a few code bits to setup support of crash hotplug
  kstrtox: consistently use _tolower()
  kill do_each_thread()
  nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
  scripts/bloat-o-meter: count weak symbol sizes
  treewide: drop CONFIG_EMBEDDED
  lockdep: fix static memory detection even more
  lib/vsprintf: declare no_hash_pointers in sprintf.h
  lib/vsprintf: split out sprintf() and friends
  kernel/fork: stop playing lockless games for exe_file replacement
  adfs: delete unused "union adfs_dirtail" definition
  ...