When KASAN is enabled, as shown by the Oops below, the 2k limit is not
enough to allow stack dump after a stack overflow detection when
CONFIG_DEBUG_STACKOVERFLOW is selected:
do_IRQ: stack overflow: 1984
CPU: 0 PID: 126 Comm: systemd-udevd Not tainted 5.18.0-gentoo-PMacG4 #1
Call Trace:
Oops: Kernel stack overflow, sig: 11 [#1]
BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2 PowerMac
Modules linked in: sr_mod cdrom radeon(+) ohci_pci(+) hwmon
i2c_algo_bit drm_ttm_helper ttm drm_dp_helper snd_aoa_i2sbus snd_aoa_soundbus
snd_pcm ehci_pci snd_timer ohci_hcd snd ssb ehci_hcd 8250_pci soundcore
drm_kms_helper pcmcia 8250 pcmcia_core syscopyarea usbcore sysfillrect
8250_base sysimgblt serial_mctrl_gpio fb_sys_fops usb_common pkcs8_key_parser
fuse drm drm_panel_orientation_quirks configfs
CPU: 0 PID: 126 Comm: systemd-udevd Not tainted 5.18.0-gentoo-PMacG4 #1
NIP: c02e5558 LR: c07eb3bc CTR: c07f46a8
REGS: e7fe9f50 TRAP: 0000 Not tainted (5.18.0-gentoo-PMacG4)
MSR: 00001032 <ME,IR,DR,RI> CR: 44a14824 XER: 20000000
GPR00: c07eb3bc eaa1c000 c26baea0 eaa1c0a0 00000008 00000000 c07eb3bc
eaa1c010
GPR08: eaa1c0a8 04f3f3f3 f1f1f1f1 c07f4c84 44a14824 0080f7e4 00000005
00000010
GPR16: 00000025 eaa1c154 eaa1c158 c0dbad64 00000020 fd543810 eaa1c0a0
eaa1c29e
GPR24: c0dbad44 c0db8740 05ffffff fd543802 eaa1c150 c0c9a3c0 eaa1c0a0
c0c9a3c0
NIP [c02e5558] kasan_check_range+0xc/0x2b4
LR [c07eb3bc] format_decode+0x80/0x604
Call Trace:
[eaa1c000] [c07eb3bc] format_decode+0x80/0x604 (unreliable)
[eaa1c070] [c07f4dac] vsnprintf+0x128/0x938
[eaa1c110] [c07f5788] sprintf+0xa0/0xc0
[eaa1c180] [c0154c1c] __sprint_symbol.constprop.0+0x170/0x198
[eaa1c230] [c07ee71c] symbol_string+0xf8/0x260
[eaa1c430] [c07f46d0] pointer+0x15c/0x710
[eaa1c4b0] [c07f4fbc] vsnprintf+0x338/0x938
[eaa1c550] [c00e8fa0] vprintk_store+0x2a8/0x678
[eaa1c690] [c00e94e4] vprintk_emit+0x174/0x378
[eaa1c6d0] [c00ea008] _printk+0x9c/0xc0
[eaa1c750] [c000ca94] show_stack+0x21c/0x260
[eaa1c7a0] [c07d0bd4] dump_stack_lvl+0x60/0x90
[eaa1c7c0] [c0009234] __do_IRQ+0x170/0x174
[eaa1c800] [c0009258] do_IRQ+0x20/0x34
[eaa1c820] [c00045b4] HardwareInterrupt_virt+0x108/0x10c
...
Increase the limit to 3k when KASAN is enabled.
While at it remove the 'inline' keywork for check_stack_overflow().
This function is called only once so it will be inlined regardless.
Reported-by: Erhard Furtner <erhar...@mailbox.org>
Cc: Arnd Bergmann <a...@arndb.de>
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
arch/powerpc/kernel/irq.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 873e6dffb868..5ff4cf69fc2f 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -53,6 +53,7 @@
#include <linux/vmalloc.h>
#include <linux/pgtable.h>
#include <linux/static_call.h>
+#include <linux/sizes.h>
#include <linux/uaccess.h>
#include <asm/interrupt.h>
@@ -184,7 +185,7 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
return sum;
}
-static inline void check_stack_overflow(void)
+static void check_stack_overflow(void)
{
long sp;
@@ -193,11 +194,14 @@ static inline void check_stack_overflow(void)
sp = current_stack_pointer & (THREAD_SIZE - 1);
- /* check for stack overflow: is there less than 2KB free? */
- if (unlikely(sp < 2048)) {
- pr_err("do_IRQ: stack overflow: %ld\n", sp);
- dump_stack();
- }
+ /* check for stack overflow: is there less than 2/3KB free? */
+ if (!IS_ENABLED(KASAN) && likely(sp >= SZ_2K))
+ return;
+ if (IS_ENABLED(KASAN) && likely(sp >= SZ_2K + SZ_1K))
+ return;
+
+ pr_err("do_IRQ: stack overflow: %ld\n", sp);
+ dump_stack();
}
static __always_inline void call_do_softirq(const void *sp)
--
2.35.3
