Changbin Du 71f46f3d1b riscv: eliminate unreliable __builtin_frame_address(1) ... commit 6a00ef4493 upstream. I tried different pieces of code which uses __builtin_frame_address(1) (with both gcc version 7.5.0 and 10.3.0) to verify whether it works as expected on riscv64. The result is negative. What the compiler had generated is as below: 31 fp = (unsigned long)__builtin_frame_address(1); 0xffffffff80006024 <+200>: ld s1,0(s0) It takes '0(s0)' as the address of frame 1 (caller), but the actual address should be '-16(s0)'. | ... | <-+ +-----------------+ | | return address | | | previous fp | | | saved registers | | | local variables | | $fp --> | ... | | +-----------------+ | | return address | | | previous fp --------+ | saved registers | $sp --> | local variables | +-----------------+ This leads the kernel can not dump the full stack trace on riscv. [ 7.222126][ T1] Call Trace: [ 7.222804][ T1] [<ffffffff80006058>] dump_backtrace+0x2c/0x3a This problem is not exposed on most riscv builds just because the '0(s0)' occasionally is the address frame 2 (caller's caller), if only ra and fp are stored in frame 1 (caller). | ... | <-+ +-----------------+ | | return address | | $fp --> | previous fp | | +-----------------+ | | return address | | | previous fp --------+ | saved registers | $sp --> | local variables | +-----------------+ This could be a *bug* of gcc that should be fixed. But as noted in gcc manual "Calling this function with a nonzero argument can have unpredictable effects, including crashing the calling program.", let's remove the '__builtin_frame_address(1)' in backtrace code. With this fix now it can show full stack trace: [ 10.444838][ T1] Call Trace: [ 10.446199][ T1] [<ffffffff8000606c>] dump_backtrace+0x2c/0x3a [ 10.447711][ T1] [<ffffffff800060ac>] show_stack+0x32/0x3e [ 10.448710][ T1] [<ffffffff80a005c0>] dump_stack_lvl+0x58/0x7a [ 10.449941][ T1] [<ffffffff80a005f6>] dump_stack+0x14/0x1c [ 10.450929][ T1] [<ffffffff804c04ee>] ubsan_epilogue+0x10/0x5a [ 10.451869][ T1] [<ffffffff804c092e>] __ubsan_handle_load_invalid_value+0x6c/0x78 [ 10.453049][ T1] [<ffffffff8018f834>] __pagevec_release+0x62/0x64 [ 10.455476][ T1] [<ffffffff80190830>] truncate_inode_pages_range+0x132/0x5be [ 10.456798][ T1] [<ffffffff80190ce0>] truncate_inode_pages+0x24/0x30 [ 10.457853][ T1] [<ffffffff8045bb04>] kill_bdev+0x32/0x3c ... Signed-off-by: Changbin Du <changbin.du@gmail.com> Fixes: eac2f3059e ("riscv: stacktrace: fix the riscv stacktrace when CONFIG_FRAME_POINTER enabled") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-02-16 12:56:18 +01:00
..
boot	riscv: dts: microchip: mpfs: Drop empty chosen node	2022-01-27 11:05:28 +01:00
configs	riscv: Get rid of MAXPHYSMEM configs	2022-01-27 11:02:49 +01:00
errata	riscv: skip errata_cip_453.o if CONFIG_ERRATA_SIFIVE_CIP_453 is disabled	2021-06-01 21:16:41 -07:00
include	RISC-V: Use common riscv_cpuid_to_hartid_mask() for both SMP=y and SMP=n	2022-01-27 11:02:50 +01:00
kernel	riscv: eliminate unreliable __builtin_frame_address(1)	2022-02-16 12:56:18 +01:00
lib	riscv: __asm_copy_to-from_user: Fix: Typos in comments	2021-07-23 17:49:12 -07:00
mm	riscv: mm: fix wrong phys_ram_base value for RV64	2022-01-27 11:02:50 +01:00
net	riscv, bpf: Fix potential NULL dereference	2021-10-28 08:14:30 -07:00
Kbuild	riscv: Allow device trees to be built into the kernel	2020-05-18 11:38:05 -07:00
Kconfig	riscv: Get rid of MAXPHYSMEM configs	2022-01-27 11:02:49 +01:00
Kconfig.debug	RISC-V: Remove EARLY_PRINTK support	2018-12-17 10:23:46 -08:00
Kconfig.erratas	riscv: enable SiFive errata CIP-453 and CIP-1200 Kconfig only if CONFIG_64BIT=y	2021-05-06 09:40:13 -07:00
Kconfig.socs	riscv: sifive: fix Kconfig errata warning	2021-06-12 17:20:50 -07:00
Makefile	riscv: fix build with binutils 2.38	2022-02-16 12:56:17 +01:00