linux/arch/arm
Grygorii Strashko 11ce4b33ae ARM: 8672/1: mm: remove tasklist locking from update_sections_early()
The below backtrace can be observed on -rt kernel with
CONFIG_DEBUG_MODULE_RONX (4.9 kernel CONFIG_DEBUG_RODATA) option enabled:

 BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:993
 in_atomic(): 1, irqs_disabled(): 128, pid: 14, name: migration/0
 1 lock held by migration/0/14:
  #0:  (tasklist_lock){+.+...}, at: [<c01183e8>] update_sections_early+0x24/0xdc
 irq event stamp: 38
 hardirqs last  enabled at (37): [<c08f6f7c>] _raw_spin_unlock_irq+0x24/0x68
 hardirqs last disabled at (38): [<c01fdfe8>] multi_cpu_stop+0xd8/0x138
 softirqs last  enabled at (0): [<c01303ec>] copy_process.part.5+0x238/0x1b64
 softirqs last disabled at (0): [<  (null)>]   (null)
 Preemption disabled at: [<c01fe244>] cpu_stopper_thread+0x80/0x10c
 CPU: 0 PID: 14 Comm: migration/0 Not tainted 4.9.21-rt16-02220-g49e319c #15
 Hardware name: Generic DRA74X (Flattened Device Tree)
 [<c0112014>] (unwind_backtrace) from [<c010d370>] (show_stack+0x10/0x14)
 [<c010d370>] (show_stack) from [<c049beb8>] (dump_stack+0xa8/0xd4)
 [<c049beb8>] (dump_stack) from [<c01631a0>] (___might_sleep+0x1bc/0x2ac)
 [<c01631a0>] (___might_sleep) from [<c08f7244>] (__rt_spin_lock+0x1c/0x30)
 [<c08f7244>] (__rt_spin_lock) from [<c08f77a4>] (rt_read_lock+0x54/0x68)
 [<c08f77a4>] (rt_read_lock) from [<c01183e8>] (update_sections_early+0x24/0xdc)
 [<c01183e8>] (update_sections_early) from [<c01184b0>] (__fix_kernmem_perms+0x10/0x1c)
 [<c01184b0>] (__fix_kernmem_perms) from [<c01fe010>] (multi_cpu_stop+0x100/0x138)
 [<c01fe010>] (multi_cpu_stop) from [<c01fe24c>] (cpu_stopper_thread+0x88/0x10c)
 [<c01fe24c>] (cpu_stopper_thread) from [<c015edc4>] (smpboot_thread_fn+0x174/0x31c)
 [<c015edc4>] (smpboot_thread_fn) from [<c015a988>] (kthread+0xf0/0x108)
 [<c015a988>] (kthread) from [<c0108818>] (ret_from_fork+0x14/0x3c)
 Freeing unused kernel memory: 1024K (c0d00000 - c0e00000)

The stop_machine() is called with cpus = NULL from fix_kernmem_perms() and
mark_rodata_ro() which means only one CPU will execute
update_sections_early() while all other CPUs will spin and wait. Hence,
it's safe to remove tasklist locking from update_sections_early(). As part
of this change also mark functions which are local to this module as
static.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2017-04-26 10:59:36 +01:00
..
boot ARM: 8661/1: dts: r7s72100: add l2 cache 2017-03-17 10:01:28 +00:00
common sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
configs ARM: deconfig: fix the moxart defconfig 2017-03-02 23:08:28 +01:00
crypto crypto: arm/crc32 - add build time test for CRC instruction support 2017-03-01 19:47:53 +08:00
firmware
include ARM: 8667/3: Fix memory attribute inconsistencies when using fixmap 2017-04-20 11:19:42 +01:00
kernel ARM: 8668/1: ftrace: Fix dynamic ftrace with DEBUG_RODATA and !FRAME_POINTER 2017-04-20 11:19:43 +01:00
kvm KVM: race-free exit from KVM_RUN without POSIX signals 2017-02-17 12:27:37 +01:00
lib ARM: 8658/1: uaccess: fix zeroing of 64-bit get_user() 2017-02-16 15:58:32 +00:00
mach-alpine ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-artpec
mach-asm9260
mach-aspeed
mach-at91
mach-axxia ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-bcm sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h> 2017-03-02 08:42:27 +01:00
mach-berlin ARM: 8646/1: mmu: decouple VECTORS_BASE from Kconfig 2017-02-28 11:06:12 +00:00
mach-clps711x
mach-cns3xxx
mach-davinci ARM: SoC platform updates 2017-02-23 15:33:54 -08:00
mach-digicolor
mach-dove
mach-ebsa110
mach-efm32
mach-ep93xx RTC for 4.11 2017-02-27 19:59:21 -08:00
mach-exynos Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-footbridge
mach-gemini
mach-highbank
mach-hisi Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-imx Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-integrator
mach-iop13xx
mach-iop32x
mach-iop33x
mach-ixp4xx
mach-keystone ARM: Keystone: Enable ARCH_HAS_RESET_CONTROLLER 2017-01-19 09:36:08 -08:00
mach-ks8695
mach-lpc18xx
mach-lpc32xx
mach-mediatek ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-meson
mach-mmp
mach-moxart
mach-mv78xx0 ARM: mv78xx0: fix possible PCI buffer overflow 2017-01-27 17:52:57 +01:00
mach-mvebu Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-mxs
mach-netx
mach-nomadik
mach-nspire
mach-omap1 ARM: SoC platform updates 2017-02-23 15:33:54 -08:00
mach-omap2 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h> 2017-03-02 08:42:27 +01:00
mach-orion5x RTC for 4.11 2017-02-27 19:59:21 -08:00
mach-oxnas
mach-picoxcell
mach-prima2 ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-pxa Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-qcom
mach-realview ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-rockchip Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-rpc sched/headers: Prepare for new header dependencies before moving code to <linux/sched/mm.h> 2017-03-02 08:42:28 +01:00
mach-s3c24xx Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-s3c64xx Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-s5pv210 Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-sa1100 ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-shmobile ARM: 8660/1: shmobile: r7s72100: Enable L2 cache 2017-03-17 10:01:27 +00:00
mach-socfpga ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-spear ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-sti ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-stm32
mach-sunxi Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-tango ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-tegra Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
mach-u300
mach-uniphier
mach-ux500 ARM: SoC: late DT updates for v4.11 2017-03-03 16:15:48 -08:00
mach-versatile
mach-vexpress ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-vt8500
mach-w90x900
mach-zx ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mach-zynq ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol 2017-02-28 11:06:10 +00:00
mm ARM: 8672/1: mm: remove tasklist locking from update_sections_early() 2017-04-26 10:59:36 +01:00
net
nwfpe sched/headers: Move task_struct::signal and task_struct::sighand types and accessors into <linux/sched/signal.h> 2017-03-03 01:43:37 +01:00
oprofile
plat-iop
plat-omap
plat-orion ARM: orion: Register DSA switch as a MDIO device 2017-02-07 10:51:47 -05:00
plat-pxa
plat-samsung
plat-versatile
probes sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h> 2017-03-02 08:42:34 +01:00
tools
vdso
vfp sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
xen This is a tree wide change and has been kept separate for that reason. 2017-02-25 13:45:43 -08:00
Kconfig ARM: 8663/1: wire up HWCAP/HWCAP2 feature bits to the CPU modalias 2017-03-30 19:45:52 +01:00
Kconfig-nommu
Kconfig.debug arch: Move CONFIG_DEBUG_RODATA and CONFIG_SET_MODULE_RONX to be common 2017-02-07 12:32:52 -08:00
Makefile