From: Balbir Singh <bsingharora@gmail.com>
I spent some time trying to use kgdb and debugged my inability to
resume from kgdb_handle_breakpoint(). NIP is not incremented
and that leads to a loop in the debugger.
I've tested this lightly on a virtual instance with KDB enabled.
After the patch, I am able to get the "go" command to work as
expected
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
---
arch/powerpc/kernel/kgdb.c | 4 ++++
1 file changed, 4 insertions(+)
@@ -445,7 +445,11 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code,*Globaldata*/structkgdb_archarch_kgdb_ops={+#ifdef __LITTLE_ENDIAN__+.gdb_bpt_instr={0x08,0x10,0x82,0x7d},+#else.gdb_bpt_instr={0x7d,0x82,0x10,0x08},+#endif /* __LITTLE_ENDIAN__ */};staticintkgdb_not_implemented(structpt_regs*regs)
From: Andrew Donnellan <hidden> Date: 2016-02-01 10:40:07
On 01/02/16 17:03, Balbir Singh wrote:
From: Balbir Singh <bsingharora@gmail.com>
I spent some time trying to use kgdb and debugged my inability to
resume from kgdb_handle_breakpoint(). NIP is not incremented
and that leads to a loop in the debugger.
I've tested this lightly on a virtual instance with KDB enabled.
After the patch, I am able to get the "go" command to work as
expected
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Should this be Cc'd to stable?
--
Andrew Donnellan Software Engineer, OzLabs
andrew.donnellan@au1.ibm.com Australia Development Lab, Canberra
+61 2 6201 8874 (work) IBM Australia Limited
On Mon, 1 Feb 2016 21:39:00 +1100
Andrew Donnellan [off-list ref] wrote:
On 01/02/16 17:03, Balbir Singh wrote:
quoted
From: Balbir Singh <bsingharora@gmail.com>
I spent some time trying to use kgdb and debugged my inability to
resume from kgdb_handle_breakpoint(). NIP is not incremented
and that leads to a loop in the debugger.
I've tested this lightly on a virtual instance with KDB enabled.
After the patch, I am able to get the "go" command to work as
expected
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Should this be Cc'd to stable?
Good suggestion, Michael? I can repost this to stable if required?
Balbir Singh.
From: Michael Ellerman <mpe@ellerman.id.au> Date: 2016-02-09 10:12:00
On Mon, 2016-01-02 at 06:03:25 UTC, Balbir Singh wrote:
From: Balbir Singh <bsingharora@gmail.com>
I spent some time trying to use kgdb and debugged my inability to
resume from kgdb_handle_breakpoint(). NIP is not incremented
and that leads to a loop in the debugger.
I've tested this lightly on a virtual instance with KDB enabled.
After the patch, I am able to get the "go" command to work as
expected
The test suite isn't working for me (I think?), so I think maybe we need
something more?
KGDB: Registered I/O driver kgdbts
kgdbts:RUN plant and detach test
Entering kdb (current=0xc0000001fefc0000, pid 1) on processor 12 due to Keyboard Entry
[12]kdb> kgdbts:RUN sw breakpoint test
kgdbts: BP mismatch c00000000018e2cc expected c00000000061c510
KGDB: re-enter exception: ALL breakpoints killed
CPU: 12 PID: 1 Comm: swapper/0 Not tainted 4.5.0-rc3-00006-g893791ee8b01 #5
Call Trace:
[c0000001fb082e10] [c0000000009c4608] dump_stack+0xb0/0xf0 (unreliable)
[c0000001fb082e50] [c00000000018fa8c] kgdb_handle_exception+0x2ac/0x2c0
[c0000001fb082f20] [c0000000000405f4] kgdb_handle_breakpoint+0x64/0xa0
[c0000001fb082f50] [c0000000009bcee4] program_check_exception+0x144/0x370
[c0000001fb082fc0] [c000000000006244] program_check_common+0x144/0x180
--- interrupt: 700 at check_and_rewind_pc+0x100/0x130
LR = check_and_rewind_pc+0xfc/0x130
[c0000001fb083340] [c00000000061bfc0] validate_simple_test+0x60/0x170
[c0000001fb083370] [c00000000061c784] run_simple_test+0x194/0x3c0
[c0000001fb0833f0] [c00000000061c17c] kgdbts_put_char+0x4c/0x70
[c0000001fb083420] [c0000000001902e0] put_packet+0x130/0x210
[c0000001fb083470] [c000000000191338] gdb_serial_stub+0x478/0x1110
[c0000001fb083560] [c00000000018f19c] kgdb_cpu_enter+0x3fc/0x800
[c0000001fb083660] [c00000000018f970] kgdb_handle_exception+0x190/0x2c0
[c0000001fb083730] [c0000000000405f4] kgdb_handle_breakpoint+0x64/0xa0
[c0000001fb083760] [c0000000009bcee4] program_check_exception+0x144/0x370
[c0000001fb0837d0] [c000000000006244] program_check_common+0x144/0x180
--- interrupt: 700 at kgdb_breakpoint+0x3c/0x70
LR = run_breakpoint_test+0xa4/0x120
[c0000001fb083ac0] [0000000000000000] (null) (unreliable)
[c0000001fb083ae0] [c00000000061d714] run_breakpoint_test+0xa4/0x120
[c0000001fb083b50] [c00000000061dcb4] configure_kgdbts+0x2c4/0x6e0
[c0000001fb083c30] [c00000000000b3d0] do_one_initcall+0xd0/0x250
[c0000001fb083d00] [c000000000cc42f8] kernel_init_freeable+0x270/0x350
[c0000001fb083dc0] [c00000000000bd3c] kernel_init+0x2c/0x150
[c0000001fb083e30] [c0000000000095b0] ret_from_kernel_thread+0x5c/0xac
Kernel panic - not syncing: Recursive entry to debugger
CPU: 12 PID: 1 Comm: swapper/0 Not tainted 4.5.0-rc3-00006-g893791ee8b01 #5
Call Trace:
[c0000001fb082d70] [c0000000009c4608] dump_stack+0xb0/0xf0 (unreliable)
[c0000001fb082db0] [c0000000009c2edc] panic+0x138/0x300
[c0000001fb082e50] [c00000000018fa9c] kgdb_handle_exception+0x2bc/0x2c0
[c0000001fb082f20] [c0000000000405f4] kgdb_handle_breakpoint+0x64/0xa0
[c0000001fb082f50] [c0000000009bcee4] program_check_exception+0x144/0x370
[c0000001fb082fc0] [c000000000006244] program_check_common+0x144/0x180
--- interrupt: 700 at check_and_rewind_pc+0x100/0x130
LR = check_and_rewind_pc+0xfc/0x130
[c0000001fb083340] [c00000000061bfc0] validate_simple_test+0x60/0x170
[c0000001fb083370] [c00000000061c784] run_simple_test+0x194/0x3c0
[c0000001fb0833f0] [c00000000061c17c] kgdbts_put_char+0x4c/0x70
[c0000001fb083420] [c0000000001902e0] put_packet+0x130/0x210
[c0000001fb083470] [c000000000191338] gdb_serial_stub+0x478/0x1110
[c0000001fb083560] [c00000000018f19c] kgdb_cpu_enter+0x3fc/0x800
[c0000001fb083660] [c00000000018f970] kgdb_handle_exception+0x190/0x2c0
[c0000001fb083730] [c0000000000405f4] kgdb_handle_breakpoint+0x64/0xa0
[c0000001fb083760] [c0000000009bcee4] program_check_exception+0x144/0x370
[c0000001fb0837d0] [c000000000006244] program_check_common+0x144/0x180
--- interrupt: 700 at kgdb_breakpoint+0x3c/0x70
LR = run_breakpoint_test+0xa4/0x120
[c0000001fb083ac0] [0000000000000000] (null) (unreliable)
[c0000001fb083ae0] [c00000000061d714] run_breakpoint_test+0xa4/0x120
[c0000001fb083b50] [c00000000061dcb4] configure_kgdbts+0x2c4/0x6e0
[c0000001fb083c30] [c00000000000b3d0] do_one_initcall+0xd0/0x250
[c0000001fb083d00] [c000000000cc42f8] kernel_init_freeable+0x270/0x350
[c0000001fb083dc0] [c00000000000bd3c] kernel_init+0x2c/0x150
[c0000001fb083e30] [c0000000000095b0] ret_from_kernel_thread+0x5c/0xac
Rebooting in 10 seconds..
cheers
On Tue, 2016-02-09 at 21:11 +1100, Michael Ellerman wrote:
On Mon, 2016-01-02 at 06:03:25 UTC, Balbir Singh wrote:
quoted
From: Balbir Singh <bsingharora@gmail.com>
I spent some time trying to use kgdb and debugged my inability to
resume from kgdb_handle_breakpoint(). NIP is not incremented
and that leads to a loop in the debugger.
I've tested this lightly on a virtual instance with KDB enabled.
After the patch, I am able to get the "go" command to work as
expected
The test suite isn't working for me (I think?), so I think maybe we need
something more?
KGDB: Registered I/O driver kgdbts
kgdbts:RUN plant and detach test
Entering kdb (current=0xc0000001fefc0000, pid 1) on processor 12 due to
Keyboard Entry
[12]kdb> kgdbts:RUN sw breakpoint test
kgdbts: BP mismatch c00000000018e2cc expected c00000000061c510
KGDB: re-enter exception: ALL breakpoints killed
CPU: 12 PID: 1 Comm: swapper/0 Not tainted 4.5.0-rc3-00006-g893791ee8b01 #5
Call Trace:
[c0000001fb082e10] [c0000000009c4608] dump_stack+0xb0/0xf0 (unreliable)
[c0000001fb082e50] [c00000000018fa8c] kgdb_handle_exception+0x2ac/0x2c0
[c0000001fb082f20] [c0000000000405f4] kgdb_handle_breakpoint+0x64/0xa0
[c0000001fb082f50] [c0000000009bcee4] program_check_exception+0x144/0x370
[c0000001fb082fc0] [c000000000006244] program_check_common+0x144/0x180
--- interrupt: 700 at check_and_rewind_pc+0x100/0x130
LR = check_and_rewind_pc+0xfc/0x130
[c0000001fb083340] [c00000000061bfc0] validate_simple_test+0x60/0x170
[c0000001fb083370] [c00000000061c784] run_simple_test+0x194/0x3c0
[c0000001fb0833f0] [c00000000061c17c] kgdbts_put_char+0x4c/0x70
[c0000001fb083420] [c0000000001902e0] put_packet+0x130/0x210
[c0000001fb083470] [c000000000191338] gdb_serial_stub+0x478/0x1110
[c0000001fb083560] [c00000000018f19c] kgdb_cpu_enter+0x3fc/0x800
[c0000001fb083660] [c00000000018f970] kgdb_handle_exception+0x190/0x2c0
[c0000001fb083730] [c0000000000405f4] kgdb_handle_breakpoint+0x64/0xa0
[c0000001fb083760] [c0000000009bcee4] program_check_exception+0x144/0x370
[c0000001fb0837d0] [c000000000006244] program_check_common+0x144/0x180
--- interrupt: 700 at kgdb_breakpoint+0x3c/0x70
LR = run_breakpoint_test+0xa4/0x120
[c0000001fb083ac0] [0000000000000000] (null) (unreliable)
[c0000001fb083ae0] [c00000000061d714] run_breakpoint_test+0xa4/0x120
[c0000001fb083b50] [c00000000061dcb4] configure_kgdbts+0x2c4/0x6e0
[c0000001fb083c30] [c00000000000b3d0] do_one_initcall+0xd0/0x250
[c0000001fb083d00] [c000000000cc42f8] kernel_init_freeable+0x270/0x350
[c0000001fb083dc0] [c00000000000bd3c] kernel_init+0x2c/0x150
[c0000001fb083e30] [c0000000000095b0] ret_from_kernel_thread+0x5c/0xac
Kernel panic - not syncing: Recursive entry to debugger
CPU: 12 PID: 1 Comm: swapper/0 Not tainted 4.5.0-rc3-00006-g893791ee8b01 #5
Call Trace:
[c0000001fb082d70] [c0000000009c4608] dump_stack+0xb0/0xf0 (unreliable)
[c0000001fb082db0] [c0000000009c2edc] panic+0x138/0x300
[c0000001fb082e50] [c00000000018fa9c] kgdb_handle_exception+0x2bc/0x2c0
[c0000001fb082f20] [c0000000000405f4] kgdb_handle_breakpoint+0x64/0xa0
[c0000001fb082f50] [c0000000009bcee4] program_check_exception+0x144/0x370
[c0000001fb082fc0] [c000000000006244] program_check_common+0x144/0x180
--- interrupt: 700 at check_and_rewind_pc+0x100/0x130
LR = check_and_rewind_pc+0xfc/0x130
[c0000001fb083340] [c00000000061bfc0] validate_simple_test+0x60/0x170
[c0000001fb083370] [c00000000061c784] run_simple_test+0x194/0x3c0
[c0000001fb0833f0] [c00000000061c17c] kgdbts_put_char+0x4c/0x70
[c0000001fb083420] [c0000000001902e0] put_packet+0x130/0x210
[c0000001fb083470] [c000000000191338] gdb_serial_stub+0x478/0x1110
[c0000001fb083560] [c00000000018f19c] kgdb_cpu_enter+0x3fc/0x800
[c0000001fb083660] [c00000000018f970] kgdb_handle_exception+0x190/0x2c0
[c0000001fb083730] [c0000000000405f4] kgdb_handle_breakpoint+0x64/0xa0
[c0000001fb083760] [c0000000009bcee4] program_check_exception+0x144/0x370
[c0000001fb0837d0] [c000000000006244] program_check_common+0x144/0x180
--- interrupt: 700 at kgdb_breakpoint+0x3c/0x70
LR = run_breakpoint_test+0xa4/0x120
[c0000001fb083ac0] [0000000000000000] (null) (unreliable)
[c0000001fb083ae0] [c00000000061d714] run_breakpoint_test+0xa4/0x120
[c0000001fb083b50] [c00000000061dcb4] configure_kgdbts+0x2c4/0x6e0
[c0000001fb083c30] [c00000000000b3d0] do_one_initcall+0xd0/0x250
[c0000001fb083d00] [c000000000cc42f8] kernel_init_freeable+0x270/0x350
[c0000001fb083dc0] [c00000000000bd3c] kernel_init+0x2c/0x150
[c0000001fb083e30] [c0000000000095b0] ret_from_kernel_thread+0x5c/0xac
Rebooting in 10 seconds..
I tried the tests with and without my changes and they both fail. I suspect its
broken on ppc64le on which I am testing. The tests require more work to fix.
I'll see if I can find some time to work on them. This patch is independent of
the current breakage
Thanks for testing the patch.
Balbir Singh
From: Michael Ellerman <mpe@ellerman.id.au> Date: 2016-02-22 09:45:56
On Mon, 2016-01-02 at 06:03:25 UTC, Balbir Singh wrote:
From: Balbir Singh <bsingharora@gmail.com>
I spent some time trying to use kgdb and debugged my inability to
resume from kgdb_handle_breakpoint(). NIP is not incremented
and that leads to a loop in the debugger.
I've tested this lightly on a virtual instance with KDB enabled.
After the patch, I am able to get the "go" command to work as
expected
Signed-off-by: Balbir Singh <bsingharora@gmail.com>