If notify_die() returns NOTIFY_STOP, honor the return value from the
handler chain invocation in die() as, through a debugger, the fault
may have been fixed. It makes sense even if ignoring the event will
make the system unstable, by allowing access through a debugger it
has been compromised already anyway. So we can remove the noreturn
attribute for die() to make our port consistent with x86, arm64,
riscv and csky.
Commit 20c0d2d44029 ("[PATCH] i386: pass proper trap numbers to die
chain handlers") may be the earliest of similar changes.
Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/mips/kernel/traps.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 246c6a6..62d6c4e 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -391,16 +391,15 @@ void show_registers(struct pt_regs *regs)
static DEFINE_RAW_SPINLOCK(die_lock);
-void __noreturn die(const char *str, struct pt_regs *regs)
+void die(const char *str, struct pt_regs *regs)
{
static int die_counter;
- int sig = SIGSEGV;
+ int ret;
oops_enter();
- if (notify_die(DIE_OOPS, str, regs, 0, current->thread.trap_nr,
- SIGSEGV) == NOTIFY_STOP)
- sig = 0;
+ ret = notify_die(DIE_OOPS, str, regs, 0,
+ current->thread.trap_nr, SIGSEGV);
console_verbose();
raw_spin_lock_irq(&die_lock);
@@ -422,7 +421,8 @@ void __noreturn die(const char *str, struct pt_regs *regs)
if (regs && kexec_should_crash(current))
crash_kexec(regs);
- make_task_dead(sig);
+ if (ret != NOTIFY_STOP)
+ make_task_dead(SIGSEGV);
}
extern struct exception_table_entry __start___dbe_table[];
--
2.1.0
Hi Tiezhu,
kernel test robot noticed the following build warnings:
[auto build test WARNING on linus/master]
[also build test WARNING on v6.5-rc6 next-20230809]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Tiezhu-Yang/MIPS-Remove-noreturn-attribute-for-die/20230814-115513
base: linus/master
patch link: https://lore.kernel.org/r/1691985181-28363-2-git-send-email-yangtiezhu%40loongson.cn
patch subject: [PATCH v2 1/3] MIPS: Remove noreturn attribute for die()
config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20230814/[email protected]/config)
compiler: mips-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230814/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All warnings (new ones prefixed by >>):
arch/mips/kernel/traps.c:370:6: warning: no previous prototype for 'show_registers' [-Wmissing-prototypes]
370 | void show_registers(struct pt_regs *regs)
| ^~~~~~~~~~~~~~
arch/mips/kernel/traps.c:447:17: warning: no previous prototype for 'do_be' [-Wmissing-prototypes]
447 | asmlinkage void do_be(struct pt_regs *regs)
| ^~~~~
arch/mips/kernel/traps.c:752:17: warning: no previous prototype for 'do_ov' [-Wmissing-prototypes]
752 | asmlinkage void do_ov(struct pt_regs *regs)
| ^~~~~
arch/mips/kernel/traps.c:874:17: warning: no previous prototype for 'do_fpe' [-Wmissing-prototypes]
874 | asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
| ^~~~~~
arch/mips/kernel/traps.c:1027:17: warning: no previous prototype for 'do_bp' [-Wmissing-prototypes]
1027 | asmlinkage void do_bp(struct pt_regs *regs)
| ^~~~~
arch/mips/kernel/traps.c:1114:17: warning: no previous prototype for 'do_tr' [-Wmissing-prototypes]
1114 | asmlinkage void do_tr(struct pt_regs *regs)
| ^~~~~
arch/mips/kernel/traps.c:1151:17: warning: no previous prototype for 'do_ri' [-Wmissing-prototypes]
1151 | asmlinkage void do_ri(struct pt_regs *regs)
| ^~~~~
arch/mips/kernel/traps.c:1402:17: warning: no previous prototype for 'do_cpu' [-Wmissing-prototypes]
1402 | asmlinkage void do_cpu(struct pt_regs *regs)
| ^~~~~~
arch/mips/kernel/traps.c:1507:17: warning: no previous prototype for 'do_msa_fpe' [-Wmissing-prototypes]
1507 | asmlinkage void do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
| ^~~~~~~~~~
arch/mips/kernel/traps.c:1527:17: warning: no previous prototype for 'do_msa' [-Wmissing-prototypes]
1527 | asmlinkage void do_msa(struct pt_regs *regs)
| ^~~~~~
arch/mips/kernel/traps.c:1548:17: warning: no previous prototype for 'do_mdmx' [-Wmissing-prototypes]
1548 | asmlinkage void do_mdmx(struct pt_regs *regs)
| ^~~~~~~
arch/mips/kernel/traps.c:1560:17: warning: no previous prototype for 'do_watch' [-Wmissing-prototypes]
1560 | asmlinkage void do_watch(struct pt_regs *regs)
| ^~~~~~~~
arch/mips/kernel/traps.c:1587:17: warning: no previous prototype for 'do_mcheck' [-Wmissing-prototypes]
1587 | asmlinkage void do_mcheck(struct pt_regs *regs)
| ^~~~~~~~~
arch/mips/kernel/traps.c: In function 'do_mcheck':
arch/mips/kernel/traps.c:1590:24: warning: variable 'prev_state' set but not used [-Wunused-but-set-variable]
1590 | enum ctx_state prev_state;
| ^~~~~~~~~~
arch/mips/kernel/traps.c: At top level:
arch/mips/kernel/traps.c:1612:17: warning: no previous prototype for 'do_mt' [-Wmissing-prototypes]
1612 | asmlinkage void do_mt(struct pt_regs *regs)
| ^~~~~
arch/mips/kernel/traps.c:1648:17: warning: no previous prototype for 'do_dsp' [-Wmissing-prototypes]
1648 | asmlinkage void do_dsp(struct pt_regs *regs)
| ^~~~~~
arch/mips/kernel/traps.c:1656:17: warning: no previous prototype for 'do_reserved' [-Wmissing-prototypes]
1656 | asmlinkage void do_reserved(struct pt_regs *regs)
| ^~~~~~~~~~~
arch/mips/kernel/traps.c:1832:17: warning: no previous prototype for 'cache_parity_error' [-Wmissing-prototypes]
1832 | asmlinkage void cache_parity_error(void)
| ^~~~~~~~~~~~~~~~~~
arch/mips/kernel/traps.c:1880:17: warning: no previous prototype for 'do_ftlb' [-Wmissing-prototypes]
1880 | asmlinkage void do_ftlb(void)
| ^~~~~~~
arch/mips/kernel/traps.c:1909:17: warning: no previous prototype for 'do_gsexc' [-Wmissing-prototypes]
1909 | asmlinkage void do_gsexc(struct pt_regs *regs, u32 diag1)
| ^~~~~~~~
arch/mips/kernel/traps.c:1944:6: warning: no previous prototype for 'ejtag_exception_handler' [-Wmissing-prototypes]
1944 | void ejtag_exception_handler(struct pt_regs *regs)
| ^~~~~~~~~~~~~~~~~~~~~~~
arch/mips/kernel/traps.c:1989:17: warning: no previous prototype for 'nmi_exception_handler' [-Wmissing-prototypes]
1989 | void __noreturn nmi_exception_handler(struct pt_regs *regs)
| ^~~~~~~~~~~~~~~~~~~~~
arch/mips/kernel/traps.c: In function 'die':
>> arch/mips/kernel/traps.c:426:1: warning: 'noreturn' function does return
426 | }
| ^
vim +/noreturn +426 arch/mips/kernel/traps.c
^1da177e4c3f41 Linus Torvalds 2005-04-16 393
84d992b55d603d Tiezhu Yang 2023-08-14 394 void die(const char *str, struct pt_regs *regs)
^1da177e4c3f41 Linus Torvalds 2005-04-16 395 {
^1da177e4c3f41 Linus Torvalds 2005-04-16 396 static int die_counter;
84d992b55d603d Tiezhu Yang 2023-08-14 397 int ret;
^1da177e4c3f41 Linus Torvalds 2005-04-16 398
8742cd23471635 Nathan Lynch 2011-09-30 399 oops_enter();
8742cd23471635 Nathan Lynch 2011-09-30 400
84d992b55d603d Tiezhu Yang 2023-08-14 401 ret = notify_die(DIE_OOPS, str, regs, 0,
84d992b55d603d Tiezhu Yang 2023-08-14 402 current->thread.trap_nr, SIGSEGV);
5dd11d5d47d248 Jason Wessel 2010-05-20 403
^1da177e4c3f41 Linus Torvalds 2005-04-16 404 console_verbose();
4d85f6afa43d36 Wu Zhangjin 2011-07-23 405 raw_spin_lock_irq(&die_lock);
41c594ab65fc89 Ralf Baechle 2006-04-05 406 bust_spinlocks(1);
ce384d83d00ee4 Yury Polyanskiy 2010-04-26 407
178086c86ac973 Ralf Baechle 2005-10-13 408 printk("%s[#%d]:\n", str, ++die_counter);
^1da177e4c3f41 Linus Torvalds 2005-04-16 409 show_registers(regs);
373d4d099761cb Rusty Russell 2013-01-21 410 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
4d85f6afa43d36 Wu Zhangjin 2011-07-23 411 raw_spin_unlock_irq(&die_lock);
d4fd1989ea142b Maxime Bizon 2006-07-20 412
8742cd23471635 Nathan Lynch 2011-09-30 413 oops_exit();
8742cd23471635 Nathan Lynch 2011-09-30 414
d4fd1989ea142b Maxime Bizon 2006-07-20 415 if (in_interrupt())
d4fd1989ea142b Maxime Bizon 2006-07-20 416 panic("Fatal exception in interrupt");
d4fd1989ea142b Maxime Bizon 2006-07-20 417
99a7a234c89017 Aaro Koskinen 2016-03-09 418 if (panic_on_oops)
d4fd1989ea142b Maxime Bizon 2006-07-20 419 panic("Fatal exception");
d4fd1989ea142b Maxime Bizon 2006-07-20 420
7aa1c8f47e7e79 Ralf Baechle 2012-10-11 421 if (regs && kexec_should_crash(current))
7aa1c8f47e7e79 Ralf Baechle 2012-10-11 422 crash_kexec(regs);
7aa1c8f47e7e79 Ralf Baechle 2012-10-11 423
84d992b55d603d Tiezhu Yang 2023-08-14 424 if (ret != NOTIFY_STOP)
84d992b55d603d Tiezhu Yang 2023-08-14 425 make_task_dead(SIGSEGV);
^1da177e4c3f41 Linus Torvalds 2005-04-16 @426 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 427
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On 08/14/2023 01:24 PM, kernel test robot wrote:
> Hi Tiezhu,
>
> kernel test robot noticed the following build warnings:
>
> [auto build test WARNING on linus/master]
> [also build test WARNING on v6.5-rc6 next-20230809]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Tiezhu-Yang/MIPS-Remove-noreturn-attribute-for-die/20230814-115513
> base: linus/master
> patch link: https://lore.kernel.org/r/1691985181-28363-2-git-send-email-yangtiezhu%40loongson.cn
> patch subject: [PATCH v2 1/3] MIPS: Remove noreturn attribute for die()
> config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20230814/[email protected]/config)
> compiler: mips-linux-gcc (GCC) 12.3.0
> reproduce: (https://download.01.org/0day-ci/archive/20230814/[email protected]/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <[email protected]>
> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
>
...
> arch/mips/kernel/traps.c: In function 'die':
>>> arch/mips/kernel/traps.c:426:1: warning: 'noreturn' function does return
> 426 | }
> | ^
Thanks for your report, the follow up patch #2 of this patch series
can silence the above warning.
[PATCH v2 2/3] MIPS: Modify the declaration for die()
https://lore.kernel.org/all/[email protected]/
Thanks,
Tiezhu