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Mon, 30 May 2022 18:20:50 +0200 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman Cc: Christophe Leroy , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Erhard Furtner , Arnd Bergmann Subject: [PATCH] powerpc/irq: Increase stack_overflow detection limit when KASAN is enabled Date: Mon, 30 May 2022 18:20:42 +0200 Message-Id: X-Mailer: git-send-email 2.35.3 MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1653927641; l=3866; s=20211009; h=from:subject:message-id; bh=AasC5R2ZlZJCNvahOum7bO7JZJQHSnMQhlxhtOFxSM8=; b=XY5hjSl0p5F392EhD9PHG2bsGIYPsoEjL+9NLTTo3xxoSIojlvnPowKPqG3aXbC1BEGpz4NqQy4g iz5BbzTLCwJUc4UQldL1C3vn/KL5jk0Hpi4zhueUKjIOer2ax146 X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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=3D4K MMU=3DHash SMP NR_CPUS=3D2 PowerMac Modules linked in: sr_mod cdrom radeon(+) ohci_pci(+) hwmon i2c_algo_bit d= rm_ttm_helper ttm drm_dp_helper snd_aoa_i2sbus snd_aoa_soundbus snd_pcm ehc= i_pci snd_timer ohci_hcd snd ssb ehci_hcd 8250_pci soundcore drm_kms_helper= pcmcia 8250 pcmcia_core syscopyarea usbcore sysfillrect 8250_base sysimgbl= t serial_mctrl_gpio fb_sys_fops usb_common pkcs8_key_parser fuse drm drm_pa= nel_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 CR: 44a14824 XER: 20000000 GPR00: c07eb3bc eaa1c000 c26baea0 eaa1c0a0 00000008 00000000 c07eb3bc eaa1= c010 GPR08: eaa1c0a8 04f3f3f3 f1f1f1f1 c07f4c84 44a14824 0080f7e4 00000005 0000= 0010 GPR16: 00000025 eaa1c154 eaa1c158 c0dbad64 00000020 fd543810 eaa1c0a0 eaa1= c29e GPR24: c0dbad44 c0db8740 05ffffff fd543802 eaa1c150 c0c9a3c0 eaa1c0a0 c0c9= a3c0 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 Cc: Arnd Bergmann Signed-off-by: Christophe Leroy --- 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 #include #include +#include =20 #include #include @@ -184,7 +185,7 @@ u64 arch_irq_stat_cpu(unsigned int cpu) return sum; } =20 -static inline void check_stack_overflow(void) +static void check_stack_overflow(void) { long sp; =20 @@ -193,11 +194,14 @@ static inline void check_stack_overflow(void) =20 sp =3D current_stack_pointer & (THREAD_SIZE - 1); =20 - /* 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 >=3D SZ_2K)) + return; + if (IS_ENABLED(KASAN) && likely(sp >=3D SZ_2K + SZ_1K)) + return; + + pr_err("do_IRQ: stack overflow: %ld\n", sp); + dump_stack(); } =20 static __always_inline void call_do_softirq(const void *sp) --=20 2.35.3