uprobes: Restrict valid_vma(false) to skip VM_SHARED vmas

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valid_vma(false) ignores ->vm_flags, this is not actually right.
We should never try to write into MAP_SHARED mapping, this can
confuse an apllication which actually writes to ->vm_file.

With this patch valid_vma(false) ignores VM_WRITE only but checks
other (immutable) bits checked by valid_vma(true). This can also
speedup uprobe_munmap() and uprobe_unregister().

Note: even after this patch _unregister can confuse the probed
application if it does mprotect(PROT_WRITE) after _register and
installs "int3", but this is hardly possible to avoid and this
doesn't differ from gdb case.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

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This commit is contained in:

Oleg Nesterov 2012-09-16 19:31:39 +02:00

parent 78a320542e

commit e40cfce626

1 changed files with 4 additions and 9 deletions

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kernel/events/uprobes.c

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