linux-toradex.git/kernel/crash_core.c, branch v6.3-rc3

mm: remove 'First tail page' members from struct page

2023-02-03T06:32:59+00:00

All former users now use the folio equivalents, so remove them from the
definition of struct page.

Link: https://lkml.kernel.org/r/20230111142915.1001531-23-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton

vmcoreinfo: warn if we exceed vmcoreinfo data size

2022-12-01T00:13:17+00:00

Though vmcoreinfo is intended to be small, at just one page, useful
information is still added to it, so we risk running out of space. 
Currently there is no runtime check to see whether the vmcoreinfo buffer
has been exhausted.  Add a warning for this case.

Currently, my static checking tool[1] indicates that a good upper bound
for vmcoreinfo size is currently 3415 bytes, but the best time to add
warnings is before the risk becomes too high.

[1] https://github.com/brenns10/kernel_stuff/blob/master/vmcoreinfosize/vmcoreinfosize.py

Link: https://lkml.kernel.org/r/20221027205008.312534-1-stephen.s.brennan@oracle.com
Signed-off-by: Stephen Brennan 
Acked-by: Baoquan He 
Cc: Dave Young 
Cc: Vivek Goyal 
Cc: Kees Cook 
Signed-off-by: Andrew Morton

vmcoreinfo: add kallsyms_num_syms symbol

2022-08-28T21:02:44+00:00

The rest of the kallsyms symbols are useless without knowing the number of
symbols in the table.  In an earlier patch, I somehow dropped the
kallsyms_num_syms symbol, so add it back in.

Link: https://lkml.kernel.org/r/20220808205410.18590-1-stephen.s.brennan@oracle.com
Fixes: 5fd8fea935a1 ("vmcoreinfo: include kallsyms symbols")
Signed-off-by: Stephen Brennan 
Cc: Baoquan He 
Cc: Dave Young 
Cc: Vivek Goyal 
Signed-off-by: Andrew Morton

kdump: round up the total memory size to 128M for crashkernel reservation

2022-07-18T00:31:40+00:00

The total memory size we get in kernel is usually slightly less than the
actual memory size because BIOS/firmware will reserve some memory region. 
So it won't export all memory as usable.

E.g, on my x86_64 kvm guest with 1G memory, the total_mem value shows:
UEFI boot with ovmf: 0x3faef000 Legacy boot kvm guest: 0x3ff7ec00

When specifying crashkernel=1G-2G:128M, if we have a 1G memory machine, we
get total size 1023M from firmware.  Then it will not fall into 1G-2G,
thus no memory reserved.  User will never know this, it is hard to let
user know the exact total value in kernel.

One way is to use dmi/smbios to get physical memory size, but it's not
reliable as well.  According to Prarit hardware vendors sometimes screw
this up.  Thus round up total size to 128M to work around this problem.

This patch is a resend of [1] and rebased onto v5.19-rc2, and the
original credit goes to Dave Young.

[1]: http://lists.infradead.org/pipermail/kexec/2018-April/020568.html

Link: https://lkml.kernel.org/r/20220627074440.187222-1-ltao@redhat.com
Signed-off-by: Tao Liu 
Acked-by: Baoquan He 
Cc: Dave Young 
Signed-off-by: Andrew Morton

vmcoreinfo: include kallsyms symbols

2022-07-18T00:31:39+00:00

The internal kallsyms tables contain information which could be quite
useful to a debugging tool in the absence of other debuginfo.  If kallsyms
is enabled, then a debugging tool could parse it and use it as a fallback
symbol table.  Combined with BTF data, live & post-mortem debuggers can
support basic operations without needing a large DWARF debuginfo file
available.  As many as five symbols are necessary to properly parse
kallsyms names and addresses.  Add these to the vmcoreinfo note.

CONFIG_KALLSYMS_ABSOLUTE_PERCPU does impact the computation of symbol
addresses.  However, a debugger can infer this configuration value by
comparing the address of _stext in the vmcoreinfo with the address
computed via kallsyms.  So there's no need to include information about
this config value in the vmcoreinfo note.

To verify that we're still well below the maximum of 4096 bytes, I created
a script[1] to compute a rough upper bound on the possible size of
vmcoreinfo.  On v5.18-rc7, the script reports 3106 bytes, and with this
patch, the maximum become 3370 bytes.

[1]: https://github.com/brenns10/kernel_stuff/blob/master/vmcoreinfosize/

Link: https://lkml.kernel.org/r/20220517000508.777145-3-stephen.s.brennan@oracle.com
Signed-off-by: Stephen Brennan 
Acked-by: Baoquan He 
Cc: Bixuan Cui 
Cc: Dave Young 
Cc: David Vernet 
Cc: "Eric W. Biederman" 
Cc: Jiri Olsa 
Cc: Kees Cook 
Cc: Nick Desaulniers 
Cc: Sami Tolvanen 
Cc: Stephen Boyd 
Cc: Vivek Goyal 
Signed-off-by: Andrew Morton

Merge tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-05-27T18:22:03+00:00

Pull misc updates from Andrew Morton:
 "The non-MM patch queue for this merge window.

  Not a lot of material this cycle. Many singleton patches against
  various subsystems. Most notably some maintenance work in ocfs2
  and initramfs"

* tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (65 commits)
  kcov: update pos before writing pc in trace function
  ocfs2: dlmfs: fix error handling of user_dlm_destroy_lock
  ocfs2: dlmfs: don't clear USER_LOCK_ATTACHED when destroying lock
  fs/ntfs: remove redundant variable idx
  fat: remove time truncations in vfat_create/vfat_mkdir
  fat: report creation time in statx
  fat: ignore ctime updates, and keep ctime identical to mtime in memory
  fat: split fat_truncate_time() into separate functions
  MAINTAINERS: add Muchun as a memcg reviewer
  proc/sysctl: make protected_* world readable
  ia64: mca: drop redundant spinlock initialization
  tty: fix deadlock caused by calling printk() under tty_port->lock
  relay: remove redundant assignment to pointer buf
  fs/ntfs3: validate BOOT sectors_per_clusters
  lib/string_helpers: fix not adding strarray to device's resource list
  kernel/crash_core.c: remove redundant check of ck_cmdline
  ELF, uapi: fixup ELF_ST_TYPE definition
  ipc/mqueue: use get_tree_nodev() in mqueue_get_tree()
  ipc: update semtimedop() to use hrtimer
  ipc/sem: remove redundant assignments
  ...

kernel/crash_core.c: remove redundant check of ck_cmdline

2022-05-13T03:38:36+00:00

At the end of get_last_crashkernel(), the judgement of ck_cmdline is
obviously unnecessary and causes redundance, let's clean it up.

Link: https://lkml.kernel.org/r/20220506104116.259323-1-sensor1010@163.com
Signed-off-by: lizhe 
Acked-by: Baoquan He 
Acked-by: Philipp Rudo 
Cc: Vivek Goyal 
Cc: Dave Young 
Signed-off-by: Andrew Morton

kdump: return -ENOENT if required cmdline option does not exist

2022-05-07T18:54:33+00:00

According to the current crashkernel=Y,low support in other ARCHes, it's
an optional command-line option. When it doesn't exist, kernel will try
to allocate minimum required memory below 4G automatically.

However, __parse_crashkernel() returns '-EINVAL' for all error cases. It
can't distinguish the nonexistent option from invalid option.

Change __parse_crashkernel() to return '-ENOENT' for the nonexistent option
case. With this change, crashkernel,low memory will take the default
value if crashkernel=,low is not specified; while crashkernel reservation
will fail and bail out if an invalid option is specified.

Signed-off-by: Zhen Lei 
Acked-by: Baoquan He 
Link: https://lore.kernel.org/r/20220506114402.365-2-thunder.leizhen@huawei.com
Signed-off-by: Catalin Marinas

kernel/crash_core: suppress unknown crashkernel parameter warning

2021-12-25T20:20:55+00:00

When booting with crashkernel= on the kernel command line a warning
similar to

    Kernel command line: ro console=ttyS0 crashkernel=256M
    Unknown kernel command line parameters "crashkernel=256M", will be passed to user space.

is printed.

This comes from crashkernel= being parsed independent from the kernel
parameter handling mechanism.  So the code in init/main.c doesn't know
that crashkernel= is a valid kernel parameter and prints this incorrect
warning.

Suppress the warning by adding a dummy early_param handler for
crashkernel=.

Link: https://lkml.kernel.org/r/20211208133443.6867-1-prudo@redhat.com
Fixes: 86d1919a4fb0 ("init: print out unknown kernel parameters")
Signed-off-by: Philipp Rudo 
Acked-by: Baoquan He 
Cc: Andrew Halaney 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kdump: use vmlinux_build_id to simplify

2021-07-08T18:48:22+00:00

We can use the vmlinux_build_id array here now instead of open coding it.
This mostly consolidates code.

Link: https://lkml.kernel.org/r/20210511003845.2429846-14-swboyd@chromium.org
Signed-off-by: Stephen Boyd 
Cc: Jiri Olsa 
Cc: Alexei Starovoitov 
Cc: Jessica Yu 
Cc: Evan Green 
Cc: Hsin-Yi Wang 
Cc: Dave Young 
Cc: Baoquan He 
Cc: Vivek Goyal 
Cc: Andy Shevchenko 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Ingo Molnar 
Cc: Konstantin Khlebnikov 
Cc: Matthew Wilcox 
Cc: Petr Mladek 
Cc: Rasmus Villemoes 
Cc: Sasha Levin 
Cc: Sergey Senozhatsky 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds