diff options
author | Steven Price <steven.price@arm.com> | 2020-02-04 04:36:42 +0300 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-02-04 06:05:25 +0300 |
commit | e47690d756a760579141560ded06ec1020dd85e8 (patch) | |
tree | b81cb0311e9b565111d512b278b77d02b260e2d4 /include | |
parent | f8f0d0b6fa203bfa363d30f34f6fecce9e5cc2f7 (diff) | |
download | linux-e47690d756a760579141560ded06ec1020dd85e8.tar.xz |
x86: mm: avoid allocating struct mm_struct on the stack
struct mm_struct is quite large (~1664 bytes) and so allocating on the
stack may cause problems as the kernel stack size is small.
Since ptdump_walk_pgd_level_core() was only allocating the structure so
that it could modify the pgd argument we can instead introduce a pgd
override in struct mm_walk and pass this down the call stack to where it
is needed.
Since the correct mm_struct is now being passed down, it is now also
unnecessary to take the mmap_sem semaphore because ptdump_walk_pgd() will
now take the semaphore on the real mm.
[steven.price@arm.com: restore missed arm64 changes]
Link: http://lkml.kernel.org/r/20200108145710.34314-1-steven.price@arm.com
Link: http://lkml.kernel.org/r/20200108145710.34314-1-steven.price@arm.com
Signed-off-by: Steven Price <steven.price@arm.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/pagewalk.h | 3 | ||||
-rw-r--r-- | include/linux/ptdump.h | 2 |
2 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h index 745a654c6ea7..b1cb6b753abb 100644 --- a/include/linux/pagewalk.h +++ b/include/linux/pagewalk.h @@ -74,6 +74,7 @@ enum page_walk_action { * mm_walk - walk_page_range data * @ops: operation to call during the walk * @mm: mm_struct representing the target process of page table walk + * @pgd: pointer to PGD; only valid with no_vma (otherwise set to NULL) * @vma: vma currently walked (NULL if walking outside vmas) * @action: next action to perform (see enum page_walk_action) * @no_vma: walk ignoring vmas (vma will always be NULL) @@ -84,6 +85,7 @@ enum page_walk_action { struct mm_walk { const struct mm_walk_ops *ops; struct mm_struct *mm; + pgd_t *pgd; struct vm_area_struct *vma; enum page_walk_action action; bool no_vma; @@ -95,6 +97,7 @@ int walk_page_range(struct mm_struct *mm, unsigned long start, void *private); int walk_page_range_novma(struct mm_struct *mm, unsigned long start, unsigned long end, const struct mm_walk_ops *ops, + pgd_t *pgd, void *private); int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops, void *private); diff --git a/include/linux/ptdump.h b/include/linux/ptdump.h index b28f3f2acf90..a67065c403c3 100644 --- a/include/linux/ptdump.h +++ b/include/linux/ptdump.h @@ -17,6 +17,6 @@ struct ptdump_state { const struct ptdump_range *range; }; -void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm); +void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd); #endif /* _LINUX_PTDUMP_H */ |