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PS2: Fix MCFS #1

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rickgaiser opened this issue Jun 8, 2015 · 0 comments
Open

PS2: Fix MCFS #1

rickgaiser opened this issue Jun 8, 2015 · 0 comments

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@rickgaiser
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Kernel version had been rebased from v2.6.35 to v3.2.

MCFS does not compile/work anymore

@rickgaiser rickgaiser changed the title Update MCFS to v3.2 Fix MCFS Jun 8, 2015
@rickgaiser rickgaiser added the bug label Jun 9, 2015
@rickgaiser rickgaiser changed the title Fix MCFS PS2: Fix MCFS Jun 9, 2015
rickgaiser pushed a commit that referenced this issue Apr 21, 2017
There are a couple of seq_files which use the single_open() interface.
This interface requires that the whole output must fit into a single
buffer.

E.g.  for /proc/stat allocation failures have been observed because an
order-4 memory allocation failed due to memory fragmentation.  In such
situations reading /proc/stat is not possible anymore.

Therefore change the seq_file code to fallback to vmalloc allocations
which will usually result in a couple of order-0 allocations and hence
also work if memory is fragmented.

For reference a call trace where reading from /proc/stat failed:

  sadc: page allocation failure: order:4, mode:0x1040d0
  CPU: 1 PID: 192063 Comm: sadc Not tainted 3.10.0-123.el7.s390x #1
  [...]
  Call Trace:
    show_stack+0x6c/0xe8
    warn_alloc_failed+0xd6/0x138
    __alloc_pages_nodemask+0x9da/0xb68
    __get_free_pages+0x2e/0x58
    kmalloc_order_trace+0x44/0xc0
    stat_open+0x5a/0xd8
    proc_reg_open+0x8a/0x140
    do_dentry_open+0x1bc/0x2c8
    finish_open+0x46/0x60
    do_last+0x382/0x10d0
    path_openat+0xc8/0x4f8
    do_filp_open+0x46/0xa8
    do_sys_open+0x114/0x1f0
    sysc_tracego+0x14/0x1a

Conflicts:
	fs/seq_file.c

Bug: 17871993
Signed-off-by: Heiko Carstens <[email protected]>
Tested-by: David Rientjes <[email protected]>
Cc: Ian Kent <[email protected]>
Cc: Hendrik Brueckner <[email protected]>
Cc: Thorsten Diehl <[email protected]>
Cc: Andrea Righi <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Stefan Bader <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Git-commit: 058504e
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Change-Id: Iad795a92fee1983c300568429a6283c48625bd9a
Signed-off-by: Jeremy Gebben <[email protected]>
Signed-off-by: Naveen Ramaraj <[email protected]>
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