linux-stable.git/arch/arm/kernel/stacktrace.c, branch v4.14.331

ARM: 9191/1: arm/stacktrace, kasan: Silence KASAN warnings in unwind_frame()

2022-05-25T06:41:18+00:00

[ Upstream commit 9be4c88bb7924f68f88cfd47d925c2d046f51a73 ]

The following KASAN warning is detected by QEMU.

==================================================================
BUG: KASAN: stack-out-of-bounds in unwind_frame+0x508/0x870
Read of size 4 at addr c36bba90 by task cat/163

CPU: 1 PID: 163 Comm: cat Not tainted 5.10.0-rc1 #40
Hardware name: ARM-Versatile Express
[] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[] (show_stack) from [] (dump_stack+0x98/0xb0)
[] (dump_stack) from [] (print_address_description.constprop.0+0x58/0x4bc)
[] (print_address_description.constprop.0) from [] (kasan_report+0x154/0x170)
[] (kasan_report) from [] (unwind_frame+0x508/0x870)
[] (unwind_frame) from [] (__save_stack_trace+0x110/0x134)
[] (__save_stack_trace) from [] (stack_trace_save+0x8c/0xb4)
[] (stack_trace_save) from [] (kasan_set_track+0x38/0x60)
[] (kasan_set_track) from [] (kasan_set_free_info+0x20/0x2c)
[] (kasan_set_free_info) from [] (__kasan_slab_free+0xec/0x120)
[] (__kasan_slab_free) from [] (kmem_cache_free+0x7c/0x334)
[] (kmem_cache_free) from [] (rcu_core+0x390/0xccc)
[] (rcu_core) from [] (__do_softirq+0x180/0x518)
[] (__do_softirq) from [] (irq_exit+0x9c/0xe0)
[] (irq_exit) from [] (__handle_domain_irq+0xb0/0x110)
[] (__handle_domain_irq) from [] (gic_handle_irq+0xa0/0xb8)
[] (gic_handle_irq) from [] (__irq_svc+0x6c/0x94)
Exception stack(0xc36bb928 to 0xc36bb970)
b920:                   c36bb9c0 00000000 c0126919 c0101228 c36bb9c0 b76d7730
b940: c36b8000 c36bb9a0 c3335b00 c01ce0d8 00000003 c36bba3c c36bb940 c36bb978
b960: c010e298 c011373c 60000013 ffffffff
[] (__irq_svc) from [] (unwind_frame+0x0/0x870)
[] (unwind_frame) from [<00000000>] (0x0)

The buggy address belongs to the page:
page:(ptrval) refcount:0 mapcount:0 mapping:00000000 index:0x0 pfn:0x636bb
flags: 0x0()
raw: 00000000 00000000 ef867764 00000000 00000000 00000000 ffffffff 00000000
page dumped because: kasan: bad access detected

addr c36bba90 is located in stack of task cat/163 at offset 48 in frame:
 stack_trace_save+0x0/0xb4

this frame has 1 object:
 [32, 48) 'trace'

Memory state around the buggy address:
 c36bb980: f1 f1 f1 f1 00 04 f2 f2 00 00 f3 f3 00 00 00 00
 c36bba00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
>c36bba80: 00 00 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
                 ^
 c36bbb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 c36bbb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

There is a same issue on x86 and has been resolved by the commit f7d27c35ddff
("x86/mm, kasan: Silence KASAN warnings in get_wchan()").
The solution could be applied to arm architecture too.

Signed-off-by: Lin Yujun 
Reported-by: He Ying 
Signed-off-by: Russell King (Oracle) 
Signed-off-by: Sasha Levin

ARM: clang: Do not rely on lr register for stacktrace

2021-11-26T10:40:28+00:00

[ Upstream commit b3ea5d56f212ad81328c82454829a736197ebccc ]

Currently the stacktrace on clang compiled arm kernel uses the 'lr'
register to find the first frame address from pt_regs. However, that
is wrong after calling another function, because the 'lr' register
is used by 'bl' instruction and never be recovered.

As same as gcc arm kernel, directly use the frame pointer (r11) of
the pt_regs to find the first frame address.

Note that this fixes kretprobe stacktrace issue only with
CONFIG_UNWINDER_FRAME_POINTER=y. For the CONFIG_UNWINDER_ARM,
we need another fix.

Signed-off-by: Masami Hiramatsu 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Sasha Levin

ARM: 8992/1: Fix unwind_frame for clang-built kernels

2020-08-21T07:48:16+00:00

commit b4d5ec9b39f8b31d98f65bc5577b5d15d93795d7 upstream.

Since clang does not push pc and sp in function prologues, the current
implementation of unwind_frame does not work. By using the previous
frame's lr/fp instead of saved pc/sp we get valid unwinds on clang-built
kernels.

The bounds check on next frame pointer must be changed as well since
there are 8 less bytes between frames.

This fixes /proc//stack.

Link: https://github.com/ClangBuiltLinux/linux/issues/912

Reported-by: Miles Chen 
Tested-by: Miles Chen 
Cc: stable@vger.kernel.org
Reviewed-by: Nick Desaulniers 
Signed-off-by: Nathan Huckleberry 
Signed-off-by: Russell King 
Signed-off-by: Greg Kroah-Hartman

ARM: 8691/1: Export save_stack_trace_tsk()

2017-09-09T15:26:42+00:00

The kernel watchdog is a great debugging tool for finding tasks that
consume a disproportionate amount of CPU time in contiguous chunks. One
can imagine building a similar watchdog for arbitrary driver threads
using save_stack_trace_tsk() and print_stack_trace(). However, this is
not viable for dynamically loaded driver modules on ARM platforms
because save_stack_trace_tsk() is not exported for those architectures.
Export save_stack_trace_tsk() for the ARM architecture to align with
x86 and support various debugging use cases such as arbitrary driver
thread watchdog timers.

Signed-off-by: Dustin Brown 
Signed-off-by: Russell King

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:34+00:00

We are going to split  out of , which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

ARM: 8172/1: Use current_stack_pointer in save_stack_trace_tsk

2014-11-13T23:58:03+00:00

Use the global current_stack_pointer to get the value of the stack pointer.
This change supports being able to compile the kernel with both gcc and clang.

Signed-off-by: Behan Webster 
Reviewed-by: Mark Charlebois 
Reviewed-by: Jan-Simon Möller 
Acked-by: Will Deacon 
Acked-by: Nicolas Pitre 
Signed-off-by: Russell King

ARM: 8049/1: ftrace/add save_stack_trace_regs() implementation

2014-05-30T00:12:32+00:00

When configure kprobe events of ftrace with "stacktrace" option enabled
in arm, there is no stacktrace was recorded after the kprobe event was
triggered. The root cause is no save_stack_trace_regs() function implemented.

Implement the save_stack_trace_regs() function in arm, then ftrace will
call this architecture-related function to record the stacktrace into
ring buffer.

After this fix, stacktrace can be recorded, for example:

 # mount -t debugfs nodev /sys/kernel/debug
 # echo "p:netrx net_rx_action" >> /sys/kernel/debug/tracing/kprobe_events
 # echo 1 > /sys/kernel/debug/tracing/events/kprobes/netrx/enable
 # echo 1 > /sys/kernel/debug/tracing/options/stacktrace
 # echo 1 > /sys/kernel/debug/tracing/tracing_on
 # ping 127.0.0.1 -c 1
 # echo 0 > /sys/kernel/debug/tracing/tracing_on

 # cat /sys/kernel/debug/tracing/trace
 # tracer: nop
 #
 # entries-in-buffer/entries-written: 12/12   #P:1
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
             <------ missing some entries ---------------->
             ping-1200  [000] dNs1   667.603250: netrx: (net_rx_action+0x0/0x1f8)
             ping-1200  [000] dNs1   667.604738: 
  => net_rx_action
  => do_softirq
  => local_bh_enable
  => ip_finish_output
  => ip_output
  => ip_local_out
  => ip_send_skb
  => ip_push_pending_frames
  => raw_sendmsg
  => inet_sendmsg
  => sock_sendmsg
  => SyS_sendto
  => ret_fast_syscall

Signed-off-by: Lin Yongting 
Acked-by: Steven Rostedt 
Signed-off-by: Russell King

ARM: stacktrace: include exception PC value in stacktrace output

2014-05-22T15:33:24+00:00

When we unwind through an exception stack, include the saved PC value
into the stack trace: this fills in an otherwise missed functions from
the trace (as indicated below):

 [] fec_enet_interrupt+0xa0/0xe8
 [] handle_irq_event_percpu+0x68/0x228
 [] handle_irq_event+0x4c/0x6c
 [] handle_fasteoi_irq+0xac/0x198
 [] generic_handle_irq+0x4c/0x60
 [] handle_IRQ+0x40/0x98
 [] gic_handle_irq+0x30/0x64
 [] __irq_svc+0x40/0x50
 [] __do_softirq+0xe0/0x2fc		<====
 [] irq_exit+0xb0/0x100
 [] handle_IRQ+0x44/0x98
 [] gic_handle_irq+0x30/0x64
 [] __irq_svc+0x40/0x50
 [] arch_cpu_idle+0x30/0x38		<====
 [] cpu_startup_entry+0xac/0x214
 [] rest_init+0x68/0x80
 [] start_kernel+0x2fc/0x358

Signed-off-by: Russell King

ARM: stacktrace: avoid listing stacktrace functions in stacktrace

2014-05-22T15:33:19+00:00

While debugging the FEC ethernet driver using stacktrace, it was noticed
that the stacktraces always begin as follows:

 [] save_stack_trace_tsk+0x0/0x98
 [] save_stack_trace+0x24/0x28
 ...

This is because the stack trace code includes the stack frames for itself.
This is incorrect behaviour, and also leads to "skip" doing the wrong
thing (which is the number of stack frames to avoid recording.)

Perversely, it does the right thing when passed a non-current thread.  Fix
this by ensuring that we have a known constant number of frames above the
main stack trace function, and always skip these.

Cc: 
Signed-off-by: Russell King

ARM: 7913/1: fix framepointer check in unwind_frame

2013-12-09T23:24:33+00:00

This patch fixes corner case when (fp + 4) overflows unsigned long,
for example: fp = 0xFFFFFFFF -> fp + 4 == 3.

Cc: 
Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Russell King