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  1. 19 5月, 2022 2 次提交
  3. 11 5月, 2022 2 次提交
  5. 08 5月, 2022 1 次提交
  7. 07 3月, 2022 1 次提交
    • M
      powerpc/code-patching: Pre-map patch area · 591b4b26
      由 Michael Ellerman 提交于 
      Paul reported a warning with DEBUG_ATOMIC_SLEEP=y:

  BUG: sleeping function called from invalid context at include/linux/sched/mm.h:256
  in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1, name: swapper/0
  preempt_count: 0, expected: 0
  ...
  Call Trace:
    dump_stack_lvl+0xa0/0xec (unreliable)
    __might_resched+0x2f4/0x310
    kmem_cache_alloc+0x220/0x4b0
    __pud_alloc+0x74/0x1d0
    hash__map_kernel_page+0x2cc/0x390
    do_patch_instruction+0x134/0x4a0
    arch_jump_label_transform+0x64/0x78
    __jump_label_update+0x148/0x180
    static_key_enable_cpuslocked+0xd0/0x120
    static_key_enable+0x30/0x50
    check_kvm_guest+0x60/0x88
    pSeries_smp_probe+0x54/0xb0
    smp_prepare_cpus+0x3e0/0x430
    kernel_init_freeable+0x20c/0x43c
    kernel_init+0x30/0x1a0
    ret_from_kernel_thread+0x5c/0x64

Peter pointed out that this is because do_patch_instruction() has
disabled interrupts, but then map_patch_area() calls map_kernel_page()
then hash__map_kernel_page() which does a sleeping memory allocation.

We only see the warning in KVM guests with SMT enabled, which is not
particularly common, or on other platforms if CONFIG_KPROBES is
disabled, also not common. The reason we don't see it in most
configurations is that another path that happens to have interrupts
enabled has allocated the required page tables for us, eg. there's a
path in kprobes init that does that. That's just pure luck though.

As Christophe suggested, the simplest solution is to do a dummy
map/unmap when we initialise the patching, so that any required page
table levels are pre-allocated before the first call to
do_patch_instruction(). This works because the unmap doesn't free any
page tables that were allocated by the map, it just clears the PTE,
leaving the page table levels there for the next map.
Reported-by: NPaul Menzel <pmenzel@molgen.mpg.de>
Debugged-by: NPeter Zijlstra <peterz@infradead.org>
Suggested-by: NChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220223015821.473097-1-mpe@ellerman.id.au
      591b4b26
  9. 23 12月, 2021 11 次提交
  11. 09 12月, 2021 1 次提交
  13. 29 11月, 2021 1 次提交
  15. 25 11月, 2021 1 次提交
  17. 07 10月, 2021 1 次提交
  19. 21 6月, 2021 1 次提交
  21. 16 6月, 2021 4 次提交
  23. 21 4月, 2021 1 次提交
  25. 26 3月, 2021 1 次提交
  27. 15 9月, 2020 1 次提交
  29. 26 7月, 2020 1 次提交
  31. 10 6月, 2020 1 次提交
    • M
      mm: don't include asm/pgtable.h if linux/mm.h is already included · e31cf2f4
      由 Mike Rapoport 提交于 
      Patch series "mm: consolidate definitions of page table accessors", v2.

The low level page table accessors (pXY_index(), pXY_offset()) are
duplicated across all architectures and sometimes more than once.  For
instance, we have 31 definition of pgd_offset() for 25 supported
architectures.

Most of these definitions are actually identical and typically it boils
down to, e.g.

static inline unsigned long pmd_index(unsigned long address)
{
        return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
}

static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
        return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
}

These definitions can be shared among 90% of the arches provided
XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined.

For architectures that really need a custom version there is always
possibility to override the generic version with the usual ifdefs magic.

These patches introduce include/linux/pgtable.h that replaces
include/asm-generic/pgtable.h and add the definitions of the page table
accessors to the new header.

This patch (of 12):

The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the
functions involving page table manipulations, e.g.  pte_alloc() and
pmd_alloc().  So, there is no point to explicitly include <asm/pgtable.h>
in the files that include <linux/mm.h>.

The include statements in such cases are remove with a simple loop:

	for f in $(git grep -l "include <linux/mm.h>") ; do
		sed -i -e '/include <asm\/pgtable.h>/ d' $f
	done
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e31cf2f4
  33. 05 6月, 2020 1 次提交
  35. 26 5月, 2020 1 次提交
  37. 18 5月, 2020 7 次提交