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Filename Latest commit message Latest commit date
Vasily Gorbik 8eb521d192 s390/ftrace: fix ftrace_update_ftrace_func implementation
commit f8c2602733c953ed7a16e060640b8e96f9d94b9b upstream.

s390 enforces DYNAMIC_FTRACE if FUNCTION_TRACER is selected.
At the same time implementation of ftrace_caller is not compliant with
HAVE_DYNAMIC_FTRACE since it doesn't provide implementation of
ftrace_update_ftrace_func() and calls ftrace_trace_function() directly.

The subtle difference is that during ftrace code patching ftrace
replaces function tracer via ftrace_update_ftrace_func() and activates
it back afterwards. Unexpected direct calls to ftrace_trace_function()
during ftrace code patching leads to nullptr-dereferences when tracing
is activated for one of functions which are used during code patching.
Those function currently are:
copy_from_kernel_nofault()
copy_from_kernel_nofault_allowed()
preempt_count_sub() [with debug_defconfig]
preempt_count_add() [with debug_defconfig]

Corresponding KASAN report:
 BUG: KASAN: nullptr-dereference in function_trace_call+0x316/0x3b0
 Read of size 4 at addr 0000000000001e08 by task migration/0/15

 CPU: 0 PID: 15 Comm: migration/0 Tainted: G B 5.13.0-41423-g08316af3644d
 Hardware name: IBM 3906 M04 704 (LPAR)
 Stopper: multi_cpu_stop+0x0/0x3e0 <- stop_machine_cpuslocked+0x1e4/0x218
 Call Trace:
  [<0000000001f77caa>] show_stack+0x16a/0x1d0
  [<0000000001f8de42>] dump_stack+0x15a/0x1b0
  [<0000000001f81d56>] print_address_description.constprop.0+0x66/0x2e0
  [<000000000082b0ca>] kasan_report+0x152/0x1c0
  [<00000000004cfd8e>] function_trace_call+0x316/0x3b0
  [<0000000001fb7082>] ftrace_caller+0x7a/0x7e
  [<00000000006bb3e6>] copy_from_kernel_nofault_allowed+0x6/0x10
  [<00000000006bb42e>] copy_from_kernel_nofault+0x3e/0xd0
  [<000000000014605c>] ftrace_make_call+0xb4/0x1f8
  [<000000000047a1b4>] ftrace_replace_code+0x134/0x1d8
  [<000000000047a6e0>] ftrace_modify_all_code+0x120/0x1d0
  [<000000000047a7ec>] __ftrace_modify_code+0x5c/0x78
  [<000000000042395c>] multi_cpu_stop+0x224/0x3e0
  [<0000000000423212>] cpu_stopper_thread+0x33a/0x5a0
  [<0000000000243ff2>] smpboot_thread_fn+0x302/0x708
  [<00000000002329ea>] kthread+0x342/0x408
  [<00000000001066b2>] __ret_from_fork+0x92/0xf0
  [<0000000001fb57fa>] ret_from_fork+0xa/0x30

 The buggy address belongs to the page:
 page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1
 flags: 0x1ffff00000001000(reserved|node=0|zone=0|lastcpupid=0x1ffff)
 raw: 1ffff00000001000 0000040000000048 0000040000000048 0000000000000000
 raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  0000000000001d00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001d80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 >0000000000001e00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
                       ^
  0000000000001e80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001f00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 ==================================================================

To fix that introduce ftrace_func callback to be called from
ftrace_caller and update it in ftrace_update_ftrace_func().

Fixes: 4cc9bed034 ("[S390] cleanup ftrace backend functions")
Cc: stable@vger.kernel.org
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-28 13:30:58 +02:00
arch s390/ftrace: fix ftrace_update_ftrace_func implementation 2021-07-28 13:30:58 +02:00
block rq-qos: fix missed wake-ups in rq_qos_throttle try two 2021-07-19 08:53:16 +02:00
certs certs: Move load_system_certificate_list to a common function 2021-06-30 08:47:55 -04:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
Documentation clocksource: Retry clock read if long delays detected 2021-07-14 16:53:18 +02:00
drivers drm/panel: raspberrypi-touchscreen: Prevent double-free 2021-07-28 13:30:58 +02:00
fs proc: Avoid mixing integer types in mem_rw() 2021-07-28 13:30:58 +02:00
include afs: Fix tracepoint string placement with built-in AFS 2021-07-28 13:30:58 +02:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc
kernel sched/fair: Fix CFS bandwidth hrtimer expiry type 2021-07-25 14:35:13 +02:00
lib lib/decompress_unlz4.c: correctly handle zero-padding around initrds. 2021-07-20 16:10:46 +02:00
LICENSES
mm mm: slab: fix kmem_cache_create failed when sysfs node not destroyed 2021-07-25 14:35:14 +02:00
net net: sched: cls_api: Fix the the wrong parameter 2021-07-28 13:30:58 +02:00
samples samples/bpf: Fix the error return code of xdp_redirect's main() 2021-07-14 16:53:30 +02:00
scripts kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set 2021-07-25 14:35:12 +02:00
security smackfs: restrict bytes count in smk_set_cipso() 2021-07-19 08:53:18 +02:00
sound ASoC: rt5631: Fix regcache sync errors on resume 2021-07-28 13:30:55 +02:00
tools bpftool: Check malloc return value in mount_bpffs_for_pin 2021-07-28 13:30:55 +02:00
usr
virt KVM: mmio: Fix use-after-free Read in kvm_vm_ioctl_unregister_coalesced_mmio 2021-07-20 16:10:40 +02:00
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.cocciconfig
.get_maintainer.ignore
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MAINTAINERS
Makefile Linux 5.4.135 2021-07-25 14:35:16 +02:00
README

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There are various text files in the Documentation/ subdirectory,
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Please read the Documentation/process/changes.rst file, as it contains the
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