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Jason Baron 909af768e8 coredump: remove VM_ALWAYSDUMP flag 
The motivation for this patchset was that I was looking at a way for a
qemu-kvm process, to exclude the guest memory from its core dump, which
can be quite large.  There are already a number of filter flags in
/proc/<pid>/coredump_filter, however, these allow one to specify 'types'
of kernel memory, not specific address ranges (which is needed in this
case).

Since there are no more vma flags available, the first patch eliminates
the need for the 'VM_ALWAYSDUMP' flag.  The flag is used internally by
the kernel to mark vdso and vsyscall pages.  However, it is simple
enough to check if a vma covers a vdso or vsyscall page without the need
for this flag.

The second patch then replaces the 'VM_ALWAYSDUMP' flag with a new
'VM_NODUMP' flag, which can be set by userspace using new madvise flags:
'MADV_DONTDUMP', and unset via 'MADV_DODUMP'.  The core dump filters
continue to work the same as before unless 'MADV_DONTDUMP' is set on the
region.

The qemu code which implements this features is at:

  http://people.redhat.com/~jbaron/qemu-dump/qemu-dump.patch

In my testing the qemu core dump shrunk from 383MB -> 13MB with this
patch.

I also believe that the 'MADV_DONTDUMP' flag might be useful for
security sensitive apps, which might want to select which areas are
dumped.

This patch:

The VM_ALWAYSDUMP flag is currently used by the coredump code to
indicate that a vma is part of a vsyscall or vdso section.  However, we
can determine if a vma is in one these sections by checking it against
the gate_vma and checking for a non-NULL return value from
arch_vma_name().  Thus, freeing a valuable vma bit.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Acked-by: Roland McGrath <roland@hack.frob.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2012-03-23 16:58:42 -07:00
..
cpufreq MIPS: errloongson2_clock: Fix build error by including linux/module.h 2011-11-10 17:59:45 +00:00
.gitignore [MIPS] Ignore vmlinux.lds generated files 2008-08-26 09:10:27 +01:00
8250-platform.c mips: remove needless include of module.h from core kernel files. 2011-10-31 19:30:57 -04:00
Makefile Merge branches 'next/ar7', 'next/ath79', 'next/bcm63xx', 'next/bmips', 'next/cavium', 'next/generic', 'next/kprobes', 'next/lantiq', 'next/perf' and 'next/raza' into mips-for-linux-next 2012-01-11 15:42:31 +01:00
asm-offsets.c MIPS: Remove unused task_struct.trap_no field. 2010-08-05 13:26:30 +01:00
binfmt_elfn32.c remove div_long_long_rem 2008-05-01 08:03:58 -07:00
binfmt_elfo32.c MIPS: 64-bit: Fix o32 core dump 2009-07-03 15:45:27 +01:00
bmips_vec.S MIPS: BMIPS: Add SMP support code for BMIPS43xx/BMIPS5000 2011-12-07 22:03:18 +00:00
branch.c MIPS Kprobes: Refactor branch emulation 2011-12-07 22:04:03 +00:00
cevt-bcm1480.c MIPS: irq: Remove IRQF_DISABLED 2011-12-07 22:03:45 +00:00
cevt-ds1287.c MIPS: irq: Remove IRQF_DISABLED 2011-12-07 22:03:45 +00:00
cevt-gt641xx.c MIPS: irq: Remove IRQF_DISABLED 2011-12-07 22:03:45 +00:00
cevt-r4k.c MIPS: irq: Remove IRQF_DISABLED 2011-12-07 22:03:45 +00:00
cevt-sb1250.c MIPS: irq: Remove IRQF_DISABLED 2011-12-07 22:03:45 +00:00
cevt-smtc.c MIPS: Add missing #inclusions of <linux/irq.h> 2010-10-07 14:08:54 +01:00
cevt-txx9.c MIPS: irq: Remove IRQF_DISABLED 2011-12-07 22:03:45 +00:00
cpu-bugs64.c Fix common misspellings 2011-03-31 11:26:23 -03:00
cpu-probe.c Merge branches 'next/ar7', 'next/ath79', 'next/bcm63xx', 'next/bmips', 'next/cavium', 'next/generic', 'next/kprobes', 'next/lantiq', 'next/perf' and 'next/raza' into mips-for-linux-next 2012-01-11 15:42:31 +01:00
csrc-bcm1480.c mips: convert to clocksource_register_hz/khz 2011-02-21 13:33:50 -08:00
csrc-ioasic.c mips: convert to clocksource_register_hz/khz 2011-02-21 13:33:50 -08:00
csrc-powertv.c mips: convert to clocksource_register_hz/khz 2011-02-21 13:33:50 -08:00
csrc-r4k.c mips: convert to clocksource_register_hz/khz 2011-02-21 13:33:50 -08:00
csrc-sb1250.c mips: convert to clocksource_register_hz/khz 2011-02-21 13:33:50 -08:00
early_printk.c [MIPS] fix sparse warning about setup_early_printk() 2008-07-15 18:44:29 +01:00
entry.S MIPS: Split do_syscall_trace into two functions. 2011-05-19 09:55:44 +01:00
ftrace.c MIPS: Ftrace: Fix the CONFIG_DYNAMIC_FTRACE=n compile 2011-09-21 17:52:04 +02:00
genex.S MIPS: Read watch registers with interrupts disabled. 2009-01-30 21:32:58 +00:00
gpio_txx9.c [MIPS] txx9: Make gpio_txx9 entirely spinlock-safe 2008-07-15 18:44:34 +01:00
head.S MIPS: Avoid potential hazard on Context register 2009-11-02 12:00:07 +01:00
i8253.c MIPS: irq: Remove IRQF_DISABLED 2011-12-07 22:03:45 +00:00
i8259.c MIPS: i8259: Mark cascade interrupt non-threaded 2011-09-21 17:52:28 +02:00
init_task.c mips: migrate core kernel file from module.h --> export.h 2011-10-31 19:30:56 -04:00
irq-gic.c MIPS: Convert the irq functions to the new names 2011-03-29 14:48:07 +02:00
irq-gt641xx.c MIPS: Convert the irq functions to the new names 2011-03-29 14:48:07 +02:00
irq-msc01.c mips: remove needless include of module.h from core kernel files. 2011-10-31 19:30:57 -04:00
irq-rm7000.c MIPS: Convert the irq functions to the new names 2011-03-29 14:48:07 +02:00
irq-rm9000.c MIPS: Convert the irq functions to the new names 2011-03-29 14:48:07 +02:00
irq.c mips: remove needless include of module.h from core kernel files. 2011-10-31 19:30:57 -04:00
irq_cpu.c MIPS: Install handlers for software IRQs 2011-07-25 17:26:54 +01:00
irq_txx9.c MIPS: Convert the irq functions to the new names 2011-03-29 14:48:07 +02:00
jump_label.c MIPS: jump label: Add MIPS support. 2011-01-18 19:30:24 +01:00
kgdb.c MIPS: Fix a typo. 2010-10-04 18:33:54 +01:00
kprobes.c MIPS Kprobes: Support branch instructions probing 2011-12-07 22:04:03 +00:00
kspd.c MIPS: kspd: Adjust confusing if indentation 2010-10-04 18:33:54 +01:00
linux32.c MIPS: Compat: Use 32-bit wrapper for compat_sys_futex. 2011-09-21 17:53:44 +02:00
machine_kexec.c
…
mcount.S MIPS: tracing: Fix the indentation of mcount.S 2010-08-05 13:26:06 +01:00
mips-mt-fpaff.c MIPS: MT: Fix build error iFPU affinity code 2010-10-25 08:12:27 -07:00
mips-mt.c mips: migrate core kernel file from module.h --> export.h 2011-10-31 19:30:56 -04:00
mips_ksyms.c mips: migrate core kernel file from module.h --> export.h 2011-10-31 19:30:56 -04:00
mips_machine.c MIPS: Add generic support for multiple machines within a single kernel 2011-01-18 19:30:21 +01:00
module.c mips: remove needless include of module.h from core kernel files. 2011-10-31 19:30:57 -04:00
octeon_switch.S update David Miller's old email address 2011-04-06 06:19:38 -07:00
perf_event.c MIPS: perf: Reorganize contents of perf support files. 2011-10-24 23:34:26 +01:00
perf_event_mipsxx.c perf: Disable PERF_SAMPLE_BRANCH_* when not supported 2012-03-05 14:55:42 +01:00
proc.c MIPS: Probe for presence of KScratch registers. 2011-01-18 19:30:22 +01:00
process.c sched/rt: Use schedule_preempt_disabled() 2012-03-01 10:28:03 +01:00
prom.c irq_domain/mips: Allow irq_domain on MIPS 2012-02-24 09:47:23 -07:00
ptrace.c audit: inline audit_syscall_entry to reduce burden on archs 2012-01-17 16:16:56 -05:00
ptrace32.c headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
r4k_fpu.S update David Miller's old email address 2011-04-06 06:19:38 -07:00
r4k_switch.S update David Miller's old email address 2011-04-06 06:19:38 -07:00
r2300_fpu.S update David Miller's old email address 2011-04-06 06:19:38 -07:00
r2300_switch.S update David Miller's old email address 2011-04-06 06:19:38 -07:00
r6000_fpu.S update David Miller's old email address 2011-04-06 06:19:38 -07:00
relocate_kernel.S
…
reset.c mips: migrate core kernel file from module.h --> export.h 2011-10-31 19:30:56 -04:00
rtlx.c MIPS: irq: Remove IRQF_DISABLED 2011-12-07 22:03:45 +00:00
scall32-o32.S MIPS: Hook up process_vm_readv and process_vm_writev system calls. 2011-11-09 00:07:56 +00:00
scall64-64.S MIPS: Hook up process_vm_readv and process_vm_writev system calls. 2011-11-09 00:07:56 +00:00
scall64-n32.S MIPS: Hook up process_vm_readv and process_vm_writev system calls. 2011-11-09 00:07:56 +00:00
scall64-o32.S MIPS: Hook up process_vm_readv and process_vm_writev system calls. 2011-11-09 00:07:56 +00:00
setup.c Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2012-01-14 13:05:21 -08:00
signal-common.h MIPS: Move signal trampolines off of the stack. 2010-04-12 17:26:15 +01:00
signal.c MIPS: Handle __put_user() sleeping. 2011-09-21 17:52:38 +02:00
signal32.c MIPS: Fix GCC-4.6 'set but not used' warning in signal*.c 2011-03-14 21:07:25 +01:00
signal_n32.c MIPS: do_sigaltstack() expects userland pointers 2010-10-18 16:59:03 +01:00
smp-bmips.c MIPS: BMIPS: smp-bmips.c does not need to include version.h 2012-02-20 18:33:17 +01:00
smp-cmp.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
smp-mt.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
smp-up.c cpumask: arch_send_call_function_ipi_mask: mips 2009-09-24 09:34:45 +09:30
smp.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
smtc-asm.S
…
smtc-proc.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
smtc.c Merge branch 'next/generic' into mips-for-linux-next 2012-01-11 15:41:47 +01:00
spinlock_test.c mips: migrate core kernel file from module.h --> export.h 2011-10-31 19:30:56 -04:00
spram.c MIPS: SPRAM: Clean up support code a little 2009-11-02 12:00:05 +01:00
stacktrace.c mips: migrate core kernel file from module.h --> export.h 2011-10-31 19:30:56 -04:00
sync-r4k.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
syscall.c MIPS: Move arch_get_unmapped_area and gang to new file. 2011-05-19 09:55:49 +01:00
time.c mips: migrate core kernel file from module.h --> export.h 2011-10-31 19:30:56 -04:00
topology.c MIPS: Add arch generic CPU hotplug 2009-06-24 18:34:40 +01:00
traps.c MIPS: traps.c: Fix typo 2012-02-20 18:33:20 +01:00
unaligned.c mips: remove needless include of module.h from core kernel files. 2011-10-31 19:30:57 -04:00
vdso.c coredump: remove VM_ALWAYSDUMP flag 2012-03-23 16:58:42 -07:00
vmlinux.lds.S MIPS: vmlinux.lds.S: remove duplicate _sdata symbol 2012-02-20 18:33:18 +01:00
vpe.c mips: remove needless include of module.h from core kernel files. 2011-10-31 19:30:57 -04:00
watch.c MIPS: Add HARDWARE_WATCHPOINTS definitions and support code. 2008-10-11 16:18:56 +01:00