When we spawn a SCSI device from an ATA device in libata-scsi
the SCSI device had no relation to the device tree.
The DT binding allows us to define port nodes under a
PATA (IDE) or SATA host controller, so we can have proper device
nodes for these devices.
If OF is enabled, walk the children of the host controller node
to see if there is a valid device tree node to assign. The reg
is used to match to ID 0 for the master device and ID 1 for the
slave device.
The corresponding device tree bindings have been accepted by
the device tree maintainers.
Cc: Chris Healy <cphealy@gmail.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the call to scsi_add_host_with_dma() in ata_scsi_add_hosts() fails,
then we may get use-after-free KASAN warns:
==================================================================
BUG: KASAN: use-after-free in kobject_put+0x24/0x180
Read of size 1 at addr ffff0026b8c80364 by task swapper/0/1
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 5.6.0-rc3-00004-g5a71b206ea82-dirty #1765
Hardware name: Huawei TaiShan 200 (Model 2280)/BC82AMDD, BIOS 2280-V2 CS V3.B160.01 02/24/2020
Call trace:
dump_backtrace+0x0/0x298
show_stack+0x14/0x20
dump_stack+0x118/0x190
print_address_description.isra.9+0x6c/0x3b8
__kasan_report+0x134/0x23c
kasan_report+0xc/0x18
__asan_load1+0x5c/0x68
kobject_put+0x24/0x180
put_device+0x10/0x20
scsi_host_put+0x10/0x18
ata_devres_release+0x74/0xb0
release_nodes+0x2d0/0x470
devres_release_all+0x50/0x78
really_probe+0x2d4/0x560
driver_probe_device+0x7c/0x148
device_driver_attach+0x94/0xa0
__driver_attach+0xa8/0x110
bus_for_each_dev+0xe8/0x158
driver_attach+0x30/0x40
bus_add_driver+0x220/0x2e0
driver_register+0xbc/0x1d0
__pci_register_driver+0xbc/0xd0
ahci_pci_driver_init+0x20/0x28
do_one_initcall+0xf0/0x608
kernel_init_freeable+0x31c/0x384
kernel_init+0x10/0x118
ret_from_fork+0x10/0x18
Allocated by task 5:
save_stack+0x28/0xc8
__kasan_kmalloc.isra.8+0xbc/0xd8
kasan_kmalloc+0xc/0x18
__kmalloc+0x1a8/0x280
scsi_host_alloc+0x44/0x678
ata_scsi_add_hosts+0x74/0x268
ata_host_register+0x228/0x488
ahci_host_activate+0x1c4/0x2a8
ahci_init_one+0xd18/0x1298
local_pci_probe+0x74/0xf0
work_for_cpu_fn+0x2c/0x48
process_one_work+0x488/0xc08
worker_thread+0x330/0x5d0
kthread+0x1c8/0x1d0
ret_from_fork+0x10/0x18
Freed by task 5:
save_stack+0x28/0xc8
__kasan_slab_free+0x118/0x180
kasan_slab_free+0x10/0x18
slab_free_freelist_hook+0xa4/0x1a0
kfree+0xd4/0x3a0
scsi_host_dev_release+0x100/0x148
device_release+0x7c/0xe0
kobject_put+0xb0/0x180
put_device+0x10/0x20
scsi_host_put+0x10/0x18
ata_scsi_add_hosts+0x210/0x268
ata_host_register+0x228/0x488
ahci_host_activate+0x1c4/0x2a8
ahci_init_one+0xd18/0x1298
local_pci_probe+0x74/0xf0
work_for_cpu_fn+0x2c/0x48
process_one_work+0x488/0xc08
worker_thread+0x330/0x5d0
kthread+0x1c8/0x1d0
ret_from_fork+0x10/0x18
There is also refcount issue, as well:
WARNING: CPU: 1 PID: 1 at lib/refcount.c:28 refcount_warn_saturate+0xf8/0x170
The issue is that we make an erroneous extra call to scsi_host_put()
for that host:
So in ahci_init_one()->ata_host_alloc_pinfo()->ata_host_alloc(), we setup
a device release method - ata_devres_release() - which intends to release
the SCSI hosts:
static void ata_devres_release(struct device *gendev, void *res)
{
...
for (i = 0; i < host->n_ports; i++) {
struct ata_port *ap = host->ports[i];
if (!ap)
continue;
if (ap->scsi_host)
scsi_host_put(ap->scsi_host);
}
...
}
However in the ata_scsi_add_hosts() error path, we also call
scsi_host_put() for the SCSI hosts.
Fix by removing the the scsi_host_put() calls in ata_scsi_add_hosts() and
leave this to ata_devres_release().
Fixes: f31871951b ("libata: separate out ata_host_alloc() and ata_host_register()")
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
AT91 defconfig for 5.7
- Add sama5d4 watchdog to at91_dt_defconfig as it is present on sam9x60
* tag 'at91-5.7-defconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux:
ARM: configs: at91: enable sama5d4 compatible watchdog
Link: https://lore.kernel.org/r/20200322085711.GA208700@piout.net
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Defconfig changes for omaps for v5.7 merge window
We want to enable some more features for omap2plus_defconfig to make it
more usable:
- Enable scururity for ext4 so setcap works
- Enable simple-pm-bus so it can be later on be configured in the dts
files as needed
- Enable zram as loadable modules as we do have devices using it
- Enable more devices for droid4 for 1-wire battery eeprom and isl29028
proximity sensor
- Enable mcpdm clocks from the PMIC as loadable modules
- Enable ina2xx_adc as loadable module
- And finally let's also omap2plus_deconfig for moved and dropped options
* tag 'omap-for-v5.7/defconfig-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
ARM: omap2plus_defconfig: Update for moved and dropped options
ARM: omap2plus_defconfig: Enable ina2xx_adc as a loadable module
ARM: omap2plus_defconfig: Enable McPDM optional PMIC clock as modules
ARM: omap2plus_defconfig: Enable more droid4 devices as loadable modules
ARM: omap2plus_defconfig: Enable zram as loadable modules
ARM: omap2plus_defconfig: Enable simple-pm-bus
ARM: omap2plus_defconfig: Enable ext4 security for setcap
Link: https://lore.kernel.org/r/pull-1584575344-983293@atomide.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
i.MX defconfig changes for 5.7:
- A seris from Li Yang to make defconfig useful for NXP LS family SoCs.
Most drivers are built as module there, but those helping boot system
with NFS are enabled built-in.
- Enable i.MX8MP pinctrl and i.MX8MM thermal driver support in
defconfig.
- Enable i.MX DRM driver support for multi_v7_defconfig.
- Enable ATMEL_MXT and AD7879 touch support for imx_v6_v7_defconfig.
* tag 'imx-defconfig-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux: (22 commits)
arm64: defconfig: Enable e1000 device
arm64: defconfig: Enable PHY devices used on QorIQ boards
arm64: defconfig: Enable RTC devices for QorIQ boards
arm64: defconfig: Enable flash device drivers for QorIQ boards
arm64: defconfig: Enable ARM Mali display driver
arm64: defconfig: Enable QorIQ GPIO driver
arm64: defconfig: Enable QorIQ IFC NAND controller driver
arm64: defconfig: Enable ARM SBSA watchdog driver
arm64: defconfig: Enable QorIQ cpufreq driver
arm64: defconfig: Enable NXP/FSL SPI controller drivers
arm64: defconfig: Enable ENETC Ethernet controller and FELIX switch
arm64: defconfig: Enable QorIQ DPAA2 drivers
arm64: defconfig: Enable QorIQ DPAA1 drivers
arm64: defconfig: Enable NXP flexcan driver
arm64: defconfig: run through savedefconfig for ordering
arm64: defconfig: Enable CONFIG_IMX8MM_THERMAL as module
arm64: defconfig: add i.MX system controller thermal support
ARM: multi_v7_defconfig: enable drm imx support
arm64: defconfig: Enable CONFIG_PCIE_LAYERSCAPE_GEN4
ARM: imx_v6_v7_defconfig: Enable TOUCHSCREEN_AD7879
...
Link: https://lore.kernel.org/r/20200318051918.32579-6-shawnguo@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Qualcomm ARM defconfig updates for v5.7
Enable QRTR and the Broadcomm bluetooth driver in the qcom_defconfig,
for usage on the 8974 devices.
* tag 'qcom-defconfig-for-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux:
ARM: qcom_defconfig: Enable QRTR
ARM: qcom_defconfig: add Broadcom bluetooth options
Link: https://lore.kernel.org/r/20200318043931.GC470201@yoga
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Qualcomm ARM64 defconfig updates for v5.7
Enable SDM845 audio, display and gpu related configs and the Truly
NT35597 panel driver, all relevant for various SDM845 based boards.
Enable IPQ6018 clocks and pinctrl and the pmic vibrator driver for
PM8916.
* tag 'qcom-arm64-defconfig-for-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux:
arm64: defconfig: Enable Qualcomm SDM845 audio configs
arm64: defconfig: Enable Truly NT35597 WQXGA panel
arm64: defconfig: Enable Qualcomm SDM845 display and gpu clocks
arm64: defconfig: Enable qcom ipq6018 clock and pinctrl
arm64: defconfig: Enable Qualcomm PM8XXX vibrator support
Link: https://lore.kernel.org/r/20200318043856.GB470201@yoga
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Samsung defconfig changes for v5.7
1. Enable Energy Model and Multi-core scheduler because they fit common
use of Exynos SoCs - mobile devices,
2. Enable more drivers for GalaxyS3/Trats2.
* tag 'samsung-defconfig-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux:
ARM: exynos_defconfig: Add more drivers for GalaxyS3/Trats2
ARM: exynos_defconfig: Enable SCHED_MC and ENERGY_MODEL
ARM: exynos_defconfig: Enable SquashFS and increase RAM block device size
Link: https://lore.kernel.org/r/20200316175652.5604-2-krzk@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This pull request contains Broadcom ARM-based SoCs defconfig changes for
v5.7, please pull the following:
- Marek enables the Raspberry Pi 4 specific drivers: GENET, thermal, and
GPIO regulator support in bcm2835_defconfig
* tag 'arm-soc/for-5.7/defconfig' of https://github.com/Broadcom/stblinux:
ARM: bcm2835_defconfig: add support for Raspberry Pi4
Link: https://lore.kernel.org/r/20200311212012.9418-1-f.fainelli@gmail.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
These macros are just used by a few files. Move them out of genhd.h,
which is included everywhere into a new standalone header.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is bio layer functionality and not related to buffer heads.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
ARM64: hisilicon: defconfig updates for 5.7
- Enable MEGARAID_SAS to be able to boot from
disk for the D06CS development board
* tag 'hisi-arm64-defconfig-for-5.7' of git://github.com/hisilicon/linux-hisi:
arm64: defconfig: Enable MEGARAID_SAS
Link: https://lore.kernel.org/r/5E61F3C1.1080909@hisilicon.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Factor out the requeue handling from the dispatch code, this will make
subsequent addition of different requeueing schemes easier.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ordered ops are started twice in sync file, once outside of inode mutex
and once inside, taking the dio semaphore. There was one error path
missing the semaphore unlock.
Fixes: aab15e8ec2 ("Btrfs: fix rare chances for data loss when doing a fast fsync")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
[ add changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
LDDIR/LDPTE is Loongson-3's acceleration for Page Table Walking. If BD
(Base Directory, the 4th page directory) is not enabled, then GDOffset
is biased by BadVAddr[63:62]. So, if GDOffset (aka. BadVAddr[47:36] for
Loongson-3) is big enough, "0b11(BadVAddr[63:62])|BadVAddr[47:36]|...."
can far beyond pg_swapper_dir. This means the pg_swapper_dir may NOT be
accessed by LDDIR correctly, so fix it by set PWDirExt in CP0_PWCtl.
Cc: <stable@vger.kernel.org>
Signed-off-by: Pei Huang <huangpei@loongson.cn>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
MIPS provides multiple definitions for the following functions:
fw_init_cmdline
__delay
__udelay
__ndelay
memmove
__rmemcpy
memcpy
__copy_user
The generic ones are defined in lib-y objects, which are overridden by
the Octeon ones when CONFIG_CAVIUM_OCTEON_SOC is enabled.
The use of EXPORT_SYMBOL in static libraries potentially causes a
problem for the llvm linker [1]. So, I want to forcibly link lib-y
objects to vmlinux when CONFIG_MODULES=y.
As a groundwork, we must fix multiple definitions that have previously
been hidden by lib-y.
If you look at lib/string.c, arch can define __HAVE_ARCH_* to opt out
the generic implementation.
Similarly, this commit adds CONFIG_HAVE_PLAT_* to allow a platform
to opt out the MIPS generic code.
[1]: https://github.com/ClangBuiltLinux/linux/issues/515
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Add generic device dts for Loongson-3 devices.
They are currently almost identical but will be different later.
Some PCH devices like PCI Host Bridge is still enabled by platform
code for now.
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Co-developed-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This is an infrastructure change that makes way for fixing this issue.
Each patch was already posted previously so this is just a cleanup of
the original mailing list thread(s) which got out of control by now.
Everything started here:
https://lore.kernel.org/lkml/AM6PR03MB5170B06F3A2B75EFB98D071AE4E60@AM6PR03MB5170.eurprd03.prod.outlook.com/
I added reviewed-by tags from the mailing list threads, except when
withdrawn.
It took a lot longer than expected to collect everything from the
mailinglist threads, since several commit messages have been infected
with typos, and they got fixed without a new patch version.
- Correct the point of no return.
- Add two new mutexes to replace cred_guard_mutex.
- Fix each use of cred_guard_mutex.
- Update documentation.
- Add a test case.
-- EWB Removed the last 2 patches they need more work
Bernd Edlinger (9):
exec: Fix a deadlock in strace
selftests/ptrace: add test cases for dead-locks
mm: docs: Fix a comment in process_vm_rw_core
kernel: doc: remove outdated comment cred.c
kernel/kcmp.c: Use new infrastructure to fix deadlocks in execve
proc: Use new infrastructure to fix deadlocks in execve
proc: io_accounting: Use new infrastructure to fix deadlocks in execve
perf: Use new infrastructure to fix deadlocks in execve
pidfd: Use new infrastructure to fix deadlocks in execve
Eric W. Biederman (5):
exec: Only compute current once in flush_old_exec
exec: Factor unshare_sighand out of de_thread and call it separately
exec: Move cleanup of posix timers on exec out of de_thread
exec: Move exec_mmap right after de_thread in flush_old_exec
exec: Add exec_update_mutex to replace cred_guard_mutex
fs/exec.c | 78 +++++++++++++++++++---------
fs/proc/base.c | 10 ++--
include/linux/binfmts.h | 8 ++-
include/linux/sched/signal.h | 9 +++-
init/init_task.c | 1 +
kernel/cred.c | 2 -
kernel/events/core.c | 12 ++---
kernel/fork.c | 5 +-
kernel/kcmp.c | 8 +--
kernel/pid.c | 4 +-
mm/process_vm_access.c | 2 +-
tools/testing/selftests/ptrace/Makefile | 4 +-
tools/testing/selftests/ptrace/vmaccess.c | 86 +++++++++++++++++++++++++++++++
13 files changed, 179 insertions(+), 50 deletions(-)
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This changes __pidfd_fget to use the new exec_update_mutex
instead of cred_guard_mutex.
This should be safe, as the credentials do not change
before exec_update_mutex is locked. Therefore whatever
file access is possible with holding the cred_guard_mutex
here is also possbile with the exec_update_mutex.
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This changes perf_event_set_clock to use the new exec_update_mutex
instead of cred_guard_mutex.
This should be safe, as the credentials are only used for reading.
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This changes do_io_accounting to use the new exec_update_mutex
instead of cred_guard_mutex.
This fixes possible deadlocks when the trace is accessing
/proc/$pid/io for instance.
This should be safe, as the credentials are only used for reading.
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This changes lock_trace to use the new exec_update_mutex
instead of cred_guard_mutex.
This fixes possible deadlocks when the trace is accessing
/proc/$pid/stack for instance.
This should be safe, as the credentials are only used for reading,
and task->mm is updated on execve under the new exec_update_mutex.
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This changes kcmp_epoll_target to use the new exec_update_mutex
instead of cred_guard_mutex.
This should be safe, as the credentials are only used for reading,
and furthermore ->mm and ->sighand are updated on execve,
but only under the new exec_update_mutex.
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This removes an outdated comment in prepare_kernel_cred.
There is no "cred_replace_mutex" any more, so the comment must
go away.
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This adds test cases for ptrace deadlocks.
Additionally fixes a compile problem in get_syscall_info.c,
observed with gcc-4.8.4:
get_syscall_info.c: In function 'get_syscall_info':
get_syscall_info.c:93:3: error: 'for' loop initial declarations are only
allowed in C99 mode
for (unsigned int i = 0; i < ARRAY_SIZE(args); ++i) {
^
get_syscall_info.c:93:3: note: use option -std=c99 or -std=gnu99 to compile
your code
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This fixes a deadlock in the tracer when tracing a multi-threaded
application that calls execve while more than one thread are running.
I observed that when running strace on the gcc test suite, it always
blocks after a while, when expect calls execve, because other threads
have to be terminated. They send ptrace events, but the strace is no
longer able to respond, since it is blocked in vm_access.
The deadlock is always happening when strace needs to access the
tracees process mmap, while another thread in the tracee starts to
execve a child process, but that cannot continue until the
PTRACE_EVENT_EXIT is handled and the WIFEXITED event is received:
strace D 0 30614 30584 0x00000000
Call Trace:
__schedule+0x3ce/0x6e0
schedule+0x5c/0xd0
schedule_preempt_disabled+0x15/0x20
__mutex_lock.isra.13+0x1ec/0x520
__mutex_lock_killable_slowpath+0x13/0x20
mutex_lock_killable+0x28/0x30
mm_access+0x27/0xa0
process_vm_rw_core.isra.3+0xff/0x550
process_vm_rw+0xdd/0xf0
__x64_sys_process_vm_readv+0x31/0x40
do_syscall_64+0x64/0x220
entry_SYSCALL_64_after_hwframe+0x44/0xa9
expect D 0 31933 30876 0x80004003
Call Trace:
__schedule+0x3ce/0x6e0
schedule+0x5c/0xd0
flush_old_exec+0xc4/0x770
load_elf_binary+0x35a/0x16c0
search_binary_handler+0x97/0x1d0
__do_execve_file.isra.40+0x5d4/0x8a0
__x64_sys_execve+0x49/0x60
do_syscall_64+0x64/0x220
entry_SYSCALL_64_after_hwframe+0x44/0xa9
This changes mm_access to use the new exec_update_mutex
instead of cred_guard_mutex.
This patch is based on the following patch by Eric W. Biederman:
"[PATCH 0/5] Infrastructure to allow fixing exec deadlocks"
Link: https://lore.kernel.org/lkml/87v9ne5y4y.fsf_-_@x220.int.ebiederm.org/
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
The cred_guard_mutex is problematic as it is held over possibly
indefinite waits for userspace. The possible indefinite waits for
userspace that I have identified are: The cred_guard_mutex is held in
PTRACE_EVENT_EXIT waiting for the tracer. The cred_guard_mutex is
held over "put_user(0, tsk->clear_child_tid)" in exit_mm(). The
cred_guard_mutex is held over "get_user(futex_offset, ...") in
exit_robust_list. The cred_guard_mutex held over copy_strings.
The functions get_user and put_user can trigger a page fault which can
potentially wait indefinitely in the case of userfaultfd or if
userspace implements part of the page fault path.
In any of those cases the userspace process that the kernel is waiting
for might make a different system call that winds up taking the
cred_guard_mutex and result in deadlock.
Holding a mutex over any of those possibly indefinite waits for
userspace does not appear necessary. Add exec_update_mutex that will
just cover updating the process during exec where the permissions and
the objects pointed to by the task struct may be out of sync.
The plan is to switch the users of cred_guard_mutex to
exec_update_mutex one by one. This lets us move forward while still
being careful and not introducing any regressions.
Link: https://lore.kernel.org/lkml/20160921152946.GA24210@dhcp22.suse.cz/
Link: https://lore.kernel.org/lkml/AM6PR03MB5170B06F3A2B75EFB98D071AE4E60@AM6PR03MB5170.eurprd03.prod.outlook.com/
Link: https://lore.kernel.org/linux-fsdevel/20161102181806.GB1112@redhat.com/
Link: https://lore.kernel.org/lkml/20160923095031.GA14923@redhat.com/
Link: https://lore.kernel.org/lkml/20170213141452.GA30203@redhat.com/
Ref: 45c1a159b85b ("Add PTRACE_O_TRACEVFORKDONE and PTRACE_O_TRACEEXIT facilities.")
Ref: 456f17cd1a28 ("[PATCH] user-vm-unlock-2.5.31-A2")
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
I have read through the code in exec_mmap and I do not see anything
that depends on sighand or the sighand lock, or on signals in anyway
so this should be safe.
This rearrangement of code has two significant benefits. It makes
the determination of passing the point of no return by testing bprm->mm
accurate. All failures prior to that point in flush_old_exec are
either truly recoverable or they are fatal.
Further this consolidates all of the possible indefinite waits for
userspace together at the top of flush_old_exec. The possible wait
for a ptracer on PTRACE_EVENT_EXIT, the possible wait for a page fault
to be resolved in clear_child_tid, and the possible wait for a page
fault in exit_robust_list.
This consolidation allows the creation of a mutex to replace
cred_guard_mutex that is not held over possible indefinite userspace
waits. Which will allow removing deadlock scenarios from the kernel.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
