Re: [PATCH v1 1/1] kernel.h: Split out panic and oops helpers
On Tue, Apr 06, 2021 at 04:31:58PM +0300, Andy Shevchenko wrote: > diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h > new file mode 100644 > index ..41e32483d7a7 > --- /dev/null > +++ b/include/linux/panic_notifier.h > @@ -0,0 +1,12 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _LINUX_PANIC_NOTIFIERS_H > +#define _LINUX_PANIC_NOTIFIERS_H > + > +#include > +#include > + > +extern struct atomic_notifier_head panic_notifier_list; > + > +extern bool crash_kexec_post_notifiers; > + > +#endif /* _LINUX_PANIC_NOTIFIERS_H */ Why is it worth it to add another file just for this? Seems like a very small file. Luis ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v1 1/1] kernel.h: Split out panic and oops helpers
On Tue, Apr 06, 2021 at 04:31:58PM +0300, Andy Shevchenko wrote:
> kernel.h is being used as a dump for all kinds of stuff for a long time.
> Here is the attempt to start cleaning it up by splitting out panic and
> oops helpers.
>
> At the same time convert users in header and lib folder to use new header.
> Though for time being include new header back to kernel.h to avoid twisted
> indirected includes for existing users.
>
> Signed-off-by: Andy Shevchenko
> ---
(I think David has tried something like this a few years ago too?)
Good idea in any case. (Be good to see kbuild do an allmodconfig build
of this though.)
Acked-by: Christian Brauner
> arch/powerpc/kernel/setup-common.c | 1 +
> arch/x86/include/asm/desc.h | 1 +
> arch/x86/kernel/cpu/mshyperv.c | 1 +
> arch/x86/kernel/setup.c | 1 +
> drivers/char/ipmi/ipmi_msghandler.c | 1 +
> drivers/remoteproc/remoteproc_core.c | 1 +
> include/asm-generic/bug.h| 3 +-
> include/linux/kernel.h | 84 +---
> include/linux/panic.h| 98
> include/linux/panic_notifier.h | 12
> kernel/hung_task.c | 1 +
> kernel/kexec_core.c | 1 +
> kernel/panic.c | 1 +
> kernel/rcu/tree.c| 2 +
> kernel/sysctl.c | 1 +
> kernel/trace/trace.c | 1 +
> 16 files changed, 126 insertions(+), 84 deletions(-)
> create mode 100644 include/linux/panic.h
> create mode 100644 include/linux/panic_notifier.h
>
> diff --git a/arch/powerpc/kernel/setup-common.c
> b/arch/powerpc/kernel/setup-common.c
> index 74a98fff2c2f..046fe21b5c3b 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -9,6 +9,7 @@
> #undef DEBUG
>
> #include
> +#include
> #include
> #include
> #include
> diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
> index 476082a83d1c..ceb12683b6d1 100644
> --- a/arch/x86/include/asm/desc.h
> +++ b/arch/x86/include/asm/desc.h
> @@ -9,6 +9,7 @@
> #include
> #include
>
> +#include
> #include
> #include
>
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index 22f13343b5da..9e5c6f2b044d 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -17,6 +17,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 59e5e0903b0c..570699eecf90 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -14,6 +14,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> diff --git a/drivers/char/ipmi/ipmi_msghandler.c
> b/drivers/char/ipmi/ipmi_msghandler.c
> index 8a0e97b33cae..e96cb5c4f97a 100644
> --- a/drivers/char/ipmi/ipmi_msghandler.c
> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> @@ -16,6 +16,7 @@
>
> #include
> #include
> +#include
> #include
> #include
> #include
> diff --git a/drivers/remoteproc/remoteproc_core.c
> b/drivers/remoteproc/remoteproc_core.c
> index 626a6b90fba2..76dd8e2b1e7e 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -20,6 +20,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
> index 76a10e0dca9f..719410b93f99 100644
> --- a/include/asm-generic/bug.h
> +++ b/include/asm-generic/bug.h
> @@ -17,7 +17,8 @@
> #endif
>
> #ifndef __ASSEMBLY__
> -#include
> +#include
> +#include
>
> #ifdef CONFIG_BUG
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 09035ac67d4b..6c5a05ac1ecb 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -14,6 +14,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -70,7 +71,6 @@
> #define lower_32_bits(n) ((u32)((n) & 0x))
>
> struct completion;
> -struct pt_regs;
> struct user;
>
> #ifdef CONFIG_PREEMPT_VOLUNTARY
> @@ -175,14 +175,6 @@ void __might_fault(const char *file, int line);
> static inline void might_fault(void) { }
> #endif
>
> -extern struct atomic_notifier_head panic_notifier_list;
> -extern long (*panic_blink)(int state);
> -__printf(1, 2)
> -void panic(const char *fmt, ...) __noreturn __cold;
> -void nmi_panic(struct pt_regs *regs, const char *msg);
> -extern void oops_enter(void);
> -extern void oops_exit(void);
> -extern bool oops_may_print(void);
> void do_exit(long error_code) __noreturn;
> void complete_and_exit(struct completion *, long) __noreturn;
>
> @@ -368,52 +360,8 @@ extern int __kernel_text_address(unsigned long addr);
> extern int kernel_text_address(unsigned long addr);
> extern int func_ptr_is_kernel_text(void *ptr);
>
>
Re: [PATCH v1 1/1] kernel.h: Split out panic and oops helpers
On Tue, Apr 06, 2021 at 04:31:58PM +0300, Andy Shevchenko wrote:
> kernel.h is being used as a dump for all kinds of stuff for a long time.
> Here is the attempt to start cleaning it up by splitting out panic and
> oops helpers.
>
> At the same time convert users in header and lib folder to use new header.
> Though for time being include new header back to kernel.h to avoid twisted
> indirected includes for existing users.
For the IPMI portion:
Acked-by: Corey Minyard
>
> Signed-off-by: Andy Shevchenko
> ---
> arch/powerpc/kernel/setup-common.c | 1 +
> arch/x86/include/asm/desc.h | 1 +
> arch/x86/kernel/cpu/mshyperv.c | 1 +
> arch/x86/kernel/setup.c | 1 +
> drivers/char/ipmi/ipmi_msghandler.c | 1 +
> drivers/remoteproc/remoteproc_core.c | 1 +
> include/asm-generic/bug.h| 3 +-
> include/linux/kernel.h | 84 +---
> include/linux/panic.h| 98
> include/linux/panic_notifier.h | 12
> kernel/hung_task.c | 1 +
> kernel/kexec_core.c | 1 +
> kernel/panic.c | 1 +
> kernel/rcu/tree.c| 2 +
> kernel/sysctl.c | 1 +
> kernel/trace/trace.c | 1 +
> 16 files changed, 126 insertions(+), 84 deletions(-)
> create mode 100644 include/linux/panic.h
> create mode 100644 include/linux/panic_notifier.h
>
> diff --git a/arch/powerpc/kernel/setup-common.c
> b/arch/powerpc/kernel/setup-common.c
> index 74a98fff2c2f..046fe21b5c3b 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -9,6 +9,7 @@
> #undef DEBUG
>
> #include
> +#include
> #include
> #include
> #include
> diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
> index 476082a83d1c..ceb12683b6d1 100644
> --- a/arch/x86/include/asm/desc.h
> +++ b/arch/x86/include/asm/desc.h
> @@ -9,6 +9,7 @@
> #include
> #include
>
> +#include
> #include
> #include
>
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index 22f13343b5da..9e5c6f2b044d 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -17,6 +17,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 59e5e0903b0c..570699eecf90 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -14,6 +14,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> diff --git a/drivers/char/ipmi/ipmi_msghandler.c
> b/drivers/char/ipmi/ipmi_msghandler.c
> index 8a0e97b33cae..e96cb5c4f97a 100644
> --- a/drivers/char/ipmi/ipmi_msghandler.c
> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> @@ -16,6 +16,7 @@
>
> #include
> #include
> +#include
> #include
> #include
> #include
> diff --git a/drivers/remoteproc/remoteproc_core.c
> b/drivers/remoteproc/remoteproc_core.c
> index 626a6b90fba2..76dd8e2b1e7e 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -20,6 +20,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
> index 76a10e0dca9f..719410b93f99 100644
> --- a/include/asm-generic/bug.h
> +++ b/include/asm-generic/bug.h
> @@ -17,7 +17,8 @@
> #endif
>
> #ifndef __ASSEMBLY__
> -#include
> +#include
> +#include
>
> #ifdef CONFIG_BUG
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 09035ac67d4b..6c5a05ac1ecb 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -14,6 +14,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -70,7 +71,6 @@
> #define lower_32_bits(n) ((u32)((n) & 0x))
>
> struct completion;
> -struct pt_regs;
> struct user;
>
> #ifdef CONFIG_PREEMPT_VOLUNTARY
> @@ -175,14 +175,6 @@ void __might_fault(const char *file, int line);
> static inline void might_fault(void) { }
> #endif
>
> -extern struct atomic_notifier_head panic_notifier_list;
> -extern long (*panic_blink)(int state);
> -__printf(1, 2)
> -void panic(const char *fmt, ...) __noreturn __cold;
> -void nmi_panic(struct pt_regs *regs, const char *msg);
> -extern void oops_enter(void);
> -extern void oops_exit(void);
> -extern bool oops_may_print(void);
> void do_exit(long error_code) __noreturn;
> void complete_and_exit(struct completion *, long) __noreturn;
>
> @@ -368,52 +360,8 @@ extern int __kernel_text_address(unsigned long addr);
> extern int kernel_text_address(unsigned long addr);
> extern int func_ptr_is_kernel_text(void *ptr);
>
> -#ifdef CONFIG_SMP
> -extern unsigned int sysctl_oops_all_cpu_backtrace;
> -#else
> -#define sysctl_oops_all_cpu_backtrace 0
> -#endif /*
Re: [PATCH v1 1/1] kernel.h: Split out panic and oops helpers
On Tue 06 Apr 08:31 CDT 2021, Andy Shevchenko wrote: > kernel.h is being used as a dump for all kinds of stuff for a long time. > Here is the attempt to start cleaning it up by splitting out panic and > oops helpers. > > At the same time convert users in header and lib folder to use new header. > Though for time being include new header back to kernel.h to avoid twisted > indirected includes for existing users. > Reviewed-by: Bjorn Andersson Regards, Bjorn ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
[PATCH v1 1/1] kernel.h: Split out panic and oops helpers
kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out panic and
oops helpers.
At the same time convert users in header and lib folder to use new header.
Though for time being include new header back to kernel.h to avoid twisted
indirected includes for existing users.
Signed-off-by: Andy Shevchenko
---
arch/powerpc/kernel/setup-common.c | 1 +
arch/x86/include/asm/desc.h | 1 +
arch/x86/kernel/cpu/mshyperv.c | 1 +
arch/x86/kernel/setup.c | 1 +
drivers/char/ipmi/ipmi_msghandler.c | 1 +
drivers/remoteproc/remoteproc_core.c | 1 +
include/asm-generic/bug.h| 3 +-
include/linux/kernel.h | 84 +---
include/linux/panic.h| 98
include/linux/panic_notifier.h | 12
kernel/hung_task.c | 1 +
kernel/kexec_core.c | 1 +
kernel/panic.c | 1 +
kernel/rcu/tree.c| 2 +
kernel/sysctl.c | 1 +
kernel/trace/trace.c | 1 +
16 files changed, 126 insertions(+), 84 deletions(-)
create mode 100644 include/linux/panic.h
create mode 100644 include/linux/panic_notifier.h
diff --git a/arch/powerpc/kernel/setup-common.c
b/arch/powerpc/kernel/setup-common.c
index 74a98fff2c2f..046fe21b5c3b 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -9,6 +9,7 @@
#undef DEBUG
#include
+#include
#include
#include
#include
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 476082a83d1c..ceb12683b6d1 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -9,6 +9,7 @@
#include
#include
+#include
#include
#include
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 22f13343b5da..9e5c6f2b044d 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -17,6 +17,7 @@
#include
#include
#include
+#include
#include
#include
#include
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 59e5e0903b0c..570699eecf90 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -14,6 +14,7 @@
#include
#include
#include
+#include
#include
#include
#include
diff --git a/drivers/char/ipmi/ipmi_msghandler.c
b/drivers/char/ipmi/ipmi_msghandler.c
index 8a0e97b33cae..e96cb5c4f97a 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -16,6 +16,7 @@
#include
#include
+#include
#include
#include
#include
diff --git a/drivers/remoteproc/remoteproc_core.c
b/drivers/remoteproc/remoteproc_core.c
index 626a6b90fba2..76dd8e2b1e7e 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -20,6 +20,7 @@
#include
#include
#include
+#include
#include
#include
#include
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 76a10e0dca9f..719410b93f99 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -17,7 +17,8 @@
#endif
#ifndef __ASSEMBLY__
-#include
+#include
+#include
#ifdef CONFIG_BUG
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 09035ac67d4b..6c5a05ac1ecb 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -14,6 +14,7 @@
#include
#include
#include
+#include
#include
#include
#include
@@ -70,7 +71,6 @@
#define lower_32_bits(n) ((u32)((n) & 0x))
struct completion;
-struct pt_regs;
struct user;
#ifdef CONFIG_PREEMPT_VOLUNTARY
@@ -175,14 +175,6 @@ void __might_fault(const char *file, int line);
static inline void might_fault(void) { }
#endif
-extern struct atomic_notifier_head panic_notifier_list;
-extern long (*panic_blink)(int state);
-__printf(1, 2)
-void panic(const char *fmt, ...) __noreturn __cold;
-void nmi_panic(struct pt_regs *regs, const char *msg);
-extern void oops_enter(void);
-extern void oops_exit(void);
-extern bool oops_may_print(void);
void do_exit(long error_code) __noreturn;
void complete_and_exit(struct completion *, long) __noreturn;
@@ -368,52 +360,8 @@ extern int __kernel_text_address(unsigned long addr);
extern int kernel_text_address(unsigned long addr);
extern int func_ptr_is_kernel_text(void *ptr);
-#ifdef CONFIG_SMP
-extern unsigned int sysctl_oops_all_cpu_backtrace;
-#else
-#define sysctl_oops_all_cpu_backtrace 0
-#endif /* CONFIG_SMP */
-
extern void bust_spinlocks(int yes);
-extern int panic_timeout;
-extern unsigned long panic_print;
-extern int panic_on_oops;
-extern int panic_on_unrecovered_nmi;
-extern int panic_on_io_nmi;
-extern int panic_on_warn;
-extern unsigned long panic_on_taint;
-extern bool panic_on_taint_nousertaint;
-extern int sysctl_panic_on_rcu_stall;
-extern int sysctl_max_rcu_stall_to_panic;
-extern int sysctl_panic_on_stackoverflow;
-
Re: [PATCH v1 1/1] kernel.h: Split out panic and oops helpers
On Tue, Apr 06, 2021 at 04:31:58PM +0300, Andy Shevchenko wrote: > kernel.h is being used as a dump for all kinds of stuff for a long time. > Here is the attempt to start cleaning it up by splitting out panic and > oops helpers. > > At the same time convert users in header and lib folder to use new header. > Though for time being include new header back to kernel.h to avoid twisted > indirected includes for existing users. > > Signed-off-by: Andy Shevchenko Acked-by: Mike Rapoport > --- > arch/powerpc/kernel/setup-common.c | 1 + > arch/x86/include/asm/desc.h | 1 + > arch/x86/kernel/cpu/mshyperv.c | 1 + > arch/x86/kernel/setup.c | 1 + > drivers/char/ipmi/ipmi_msghandler.c | 1 + > drivers/remoteproc/remoteproc_core.c | 1 + > include/asm-generic/bug.h| 3 +- > include/linux/kernel.h | 84 +--- > include/linux/panic.h| 98 > include/linux/panic_notifier.h | 12 > kernel/hung_task.c | 1 + > kernel/kexec_core.c | 1 + > kernel/panic.c | 1 + > kernel/rcu/tree.c| 2 + > kernel/sysctl.c | 1 + > kernel/trace/trace.c | 1 + > 16 files changed, 126 insertions(+), 84 deletions(-) > create mode 100644 include/linux/panic.h > create mode 100644 include/linux/panic_notifier.h > > diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h > index 476082a83d1c..ceb12683b6d1 100644 > --- a/arch/x86/include/asm/desc.h > +++ b/arch/x86/include/asm/desc.h > @@ -9,6 +9,7 @@ > #include > #include > > +#include This seems unrelated, but I might be missing something. > #include > #include > -- Sincerely yours, Mike. ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH v1 1/1] kernel.h: Split out panic and oops helpers
On Tue, Apr 6, 2021 at 3:31 PM Andy Shevchenko wrote: > > kernel.h is being used as a dump for all kinds of stuff for a long time. > Here is the attempt to start cleaning it up by splitting out panic and > oops helpers. > > At the same time convert users in header and lib folder to use new header. > Though for time being include new header back to kernel.h to avoid twisted > indirected includes for existing users. > > Signed-off-by: Andy Shevchenko Nice! Acked-by: Arnd Bergmann ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
[PATCH 2/2] Shrink segments to fit alignment instead of throwing them away
From: Hongyan Xia
We risk throwing an entire large chunk away if it is just slightly
unaligned which then causes the crash kernel to run out of RAM. Keep
them and shrink them to alignment.
Signed-off-by: Hongyan Xia
---
kexec/arch/i386/crashdump-x86.c | 15 ---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c
index c79791f2b3e0..3fcb19ad76d6 100644
--- a/kexec/arch/i386/crashdump-x86.c
+++ b/kexec/arch/i386/crashdump-x86.c
@@ -475,9 +475,18 @@ static int add_memmap(struct memory_range *memmap_p, int
*nr_memmap,
int i, j, nr_entries = 0, tidx = 0, align = 1024;
unsigned long long mstart, mend;
- /* Do alignment check if it's RANGE_RAM */
- if ((type == RANGE_RAM) && ((addr%align) || (size%align)))
- return -1;
+ /* Shrink to 1KiB alignment if needed. */
+ if (type == RANGE_RAM && ((addr%align) || (size%align))) {
+ unsigned long long end = addr + size;
+
+ printf("%s: RAM chunk %#llx - %#llx unaligned\n", __func__,
addr, end);
+ addr = _ALIGN_UP(addr, align);
+ end = _ALIGN_DOWN(end, align);
+ if (addr >= end)
+ return -1;
+ size = end - addr;
+ printf("%s: RAM chunk shrunk to %#llx - %#llx\n", __func__,
addr, end);
+ }
/* Make sure at least one entry in list is free. */
for (i = 0; i < CRASH_MAX_MEMMAP_NR; i++) {
--
2.23.3
___
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[PATCH 0/2] Fix early boot OOM issues for some platforms
From: Hongyan Xia We have observed a couple of cases where after a successful kexec, the crash kernel loaded in the 2nd kernel will run out of memory and crash. We narrowed down to two issues: 1. when preparing the memory map, kexec excludes the Interrupt Vector Table. However, the end address of IVT is incorrect. 2. The wrong end address of IVT is not 1KiB aligned. When preparing the crashkernel, the memory map will reject unaligned memory chunks. On many x86 platforms this means the entire bottom 1MiB range is excluded from the crashkernel memory map, resulting in OOM when the crashkernel boots. Patch 1 fixes 1 which is actually enough to eliminate the issue but we feel that such issue may happen again (e.g., with a weird BIOS that has unaligned e820 map), so we also have patch 2 to improve the handling of unaligned memory. Hongyan Xia (2): Fix where the real mode interrupt vector ends Shrink segments to fit alignment instead of throwing them away kexec/arch/i386/crashdump-x86.c| 15 --- kexec/arch/i386/kexec-x86-common.c | 10 -- 2 files changed, 20 insertions(+), 5 deletions(-) -- 2.23.3 ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
[PATCH 1/2] Fix where the real mode interrupt vector ends
From: Hongyan Xia
The real mode ends at 0x400, not 0x100. The code intentionally excludes
the IVT as RAM, so use the correct address.
Also, 0x100 is not 1K aligned and will be rejected by add_memmap(). We
have observed problems that after a multiboot2 kexec, the next kexec
will throw away such unaligned chunks, losing memory for the next next
kernel. In some corner cases, such loss of memory can actually cause OOM
during boot.
Signed-off-by: Hongyan Xia
---
kexec/arch/i386/kexec-x86-common.c | 10 --
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/kexec/arch/i386/kexec-x86-common.c
b/kexec/arch/i386/kexec-x86-common.c
index 9303704a0714..ffc95a9e43f8 100644
--- a/kexec/arch/i386/kexec-x86-common.c
+++ b/kexec/arch/i386/kexec-x86-common.c
@@ -48,6 +48,12 @@
#define E820_PRAM 12
#endif
+/*
+ * The real mode IVT ends at 0x400.
+ * See https://wiki.osdev.org/Interrupt_Vector_Table.
+ */
+#define REALMODE_IVT_END 0x400
+
static struct memory_range memory_range[MAX_MEMORY_RANGES];
/**
@@ -360,8 +366,8 @@ int get_memory_ranges(struct memory_range **range, int
*ranges,
/* Don't report the interrupt table as ram */
for (i = 0; i < *ranges; i++) {
if ((*range)[i].type == RANGE_RAM &&
- ((*range)[i].start < 0x100)) {
- (*range)[i].start = 0x100;
+ ((*range)[i].start < REALMODE_IVT_END)) {
+ (*range)[i].start = REALMODE_IVT_END;
break;
}
}
--
2.23.3
___
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Re: [PATCH printk v2 2/5] printk: remove safe buffers
On Fri 2021-04-02 11:14:18, Sergey Senozhatsky wrote: > On (21/04/01 16:17), Petr Mladek wrote: > > > For the long term, we should introduce a printk-context API that allows > > > callers to perfectly pack their multi-line output into a single > > > entry. We discussed [0][1] this back in August 2020. > > > > We need a "short" term solution. There are currently 3 solutions: > > > > 1. Keep nmi_safe() and all the hacks around. > > > > 2. Serialize nmi_cpu_backtrace() by a spin lock and later by > >the special lock used also by atomic consoles. > > > > 3. Tell complaining people how to sort the messed logs. > > Are we talking about nmi_cpu_backtrace()->dump_stack() or some > other path? It is about serializing if (regs) show_regs(regs); else dump_stack(); in nmi_cpu_backtrace() when it is triggered on many(all) CPUs at the same time. > dump_stack() seems to be already serialized by `dump_lock`. Hmm, > show_regs() is not serialized, seems like it should be under the > same `dump_lock` as dump_stack(). Ah, I think that you already mentioned it in the past and I forget it. Yes, we would need to synchronize all these dump/show functions using the same lock. It is already the lock that might be taken recursively on the same CPU. In each case, we must not introduce another lock in nmi_cpu_backtrace() because it might cause deadlock with @dump_lock. Anyway, I would really like to keep the dumps serialized. So, we either need to use the same lock everywhere or we need to keep nmi_safe buffers for now. I would like to remove the nmi_safe buffers in the long term but I am fine with doing it later after the consoles rework. I'll leave the prioritization for John who is doing the work and might have some preferences. Best Regards, Petr ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [PATCH printk v2 2/5] printk: remove safe buffers
On 2021-04-01, Petr Mladek wrote: >> Caller-id solves this problem and is easy to sort for anyone with >> `grep'. Yes, it is a shame that `dmesg' does not show it, but >> directly using any of the printk interfaces does show it (kmsg_dump, >> /dev/kmsg, syslog, console). > > True but frankly, the current situation is _far_ from convenient: > >+ consoles do not show it by default >+ none userspace tool (dmesg, journalctl, crash) is able to show it >+ grep is a nightmare, especially if you have more than handful of CPUs > > Yes, everything is solvable but not easily. > >> > I get this with "echo l >/proc/sysrq-trigger" and this patchset: >> >> Of course. Without caller-id, it is a mess. But this has nothing to do >> with NMI. The same problem exists for WARN_ON() on multiple CPUs >> simultaneously. If the user is not using caller-id, they are >> lost. Caller-id is the current solution to the interlaced logs. > > Sure. But in reality, the risk of mixed WARN_ONs is small. While > this patch makes backtraces from all CPUs always unusable without > caller_id and non-trivial effort. I would prefer we solve the situation for non-NMI as well, not just for the sysrq "l" case. >> For the long term, we should introduce a printk-context API that allows >> callers to perfectly pack their multi-line output into a single >> entry. We discussed [0][1] this back in August 2020. > > We need a "short" term solution. There are currently 3 solutions: > > 1. Keep nmi_safe() and all the hacks around. > > 2. Serialize nmi_cpu_backtrace() by a spin lock and later by >the special lock used also by atomic consoles. > > 3. Tell complaining people how to sort the messed logs. Or we look into the long term solution now. If caller-id's cannot not be used as the solution (because nobody turns it on, nobody knows about it, and/or distros do not enable it), then we should look at how to make at least the backtraces contiguous. I have a few ideas here. John Ogness ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
