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Revision 9aea5a65aa7a1af9a4236dfaeb0088f1624f9919 authored by Roland McGrath on 08 September 2010, 02:37:06 UTC, committed by Linus Torvalds on 10 September 2010, 15:10:26 UTC 
execve: make responsive to SIGKILL with large arguments
 
An execve with a very large total of argument/environment strings
can take a really long time in the execve system call.  It runs
uninterruptibly to count and copy all the strings.  This change
makes it abort the exec quickly if sent a SIGKILL.

Note that this is the conservative change, to interrupt only for
SIGKILL, by using fatal_signal_pending().  It would be perfectly
correct semantics to let any signal interrupt the string-copying in
execve, i.e. use signal_pending() instead of fatal_signal_pending().
We'll save that change for later, since it could have user-visible
consequences, such as having a timer set too quickly make it so that
an execve can never complete, though it always happened to work before.

Signed-off-by: Roland McGrath <roland@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 7993bc1
Raw File
Makefile 
#
# kbuild file for usr/ - including initramfs image
#

klibcdirs:;
PHONY += klibcdirs


# Gzip
suffix_$(CONFIG_INITRAMFS_COMPRESSION_GZIP)   = .gz

# Bzip2
suffix_$(CONFIG_INITRAMFS_COMPRESSION_BZIP2)  = .bz2

# Lzma
suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZMA)   = .lzma

# Lzo
suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZO)   = .lzo

# Generate builtin.o based on initramfs_data.o
obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data$(suffix_y).o

# initramfs_data.o contains the compressed initramfs_data.cpio image.
# The image is included using .incbin, a dependency which is not
# tracked automatically.
$(obj)/initramfs_data$(suffix_y).o: $(obj)/initramfs_data.cpio$(suffix_y) FORCE

#####
# Generate the initramfs cpio archive

hostprogs-y := gen_init_cpio
initramfs   := $(CONFIG_SHELL) $(srctree)/scripts/gen_initramfs_list.sh
ramfs-input := $(if $(filter-out "",$(CONFIG_INITRAMFS_SOURCE)), \
			$(shell echo $(CONFIG_INITRAMFS_SOURCE)),-d)
ramfs-args  := \
        $(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID)) \
        $(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID))

# .initramfs_data.cpio.d is used to identify all files included
# in initramfs and to detect if any files are added/removed.
# Removed files are identified by directory timestamp being updated
# The dependency list is generated by gen_initramfs.sh -l
ifneq ($(wildcard $(obj)/.initramfs_data.cpio.d),)
	include $(obj)/.initramfs_data.cpio.d
endif

quiet_cmd_initfs = GEN     $@
      cmd_initfs = $(initramfs) -o $@ $(ramfs-args) $(ramfs-input)

targets := initramfs_data.cpio.gz initramfs_data.cpio.bz2 initramfs_data.cpio.lzma initramfs_data.cpio.lzo initramfs_data.cpio
# do not try to update files included in initramfs
$(deps_initramfs): ;

$(deps_initramfs): klibcdirs
# We rebuild initramfs_data.cpio if:
# 1) Any included file is newer then initramfs_data.cpio
# 2) There are changes in which files are included (added or deleted)
# 3) If gen_init_cpio are newer than initramfs_data.cpio
# 4) arguments to gen_initramfs.sh changes
$(obj)/initramfs_data.cpio$(suffix_y): $(obj)/gen_init_cpio $(deps_initramfs) klibcdirs
	$(Q)$(initramfs) -l $(ramfs-input) > $(obj)/.initramfs_data.cpio.d
	$(call if_changed,initfs)
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