diff options
| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2018-10-06 18:51:14 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-10-13 13:21:25 +0200 |
| commit | fb2d9505c0dbd4f5e00db70f7ca0ca7a3d75ca63 (patch) | |
| tree | 7cd8733510170de72e5bdf7fc68d5c884802ece2 /arch/powerpc | |
| parent | powerpc/process: Add missing include of stacktrace.h (diff) | |
| download | linux-fb2d9505c0dbd4f5e00db70f7ca0ca7a3d75ca63.tar.xz linux-fb2d9505c0dbd4f5e00db70f7ca0ca7a3d75ca63.zip | |
powerpc/process: Fix interleaved output in show_user_instructions()
When two processes crash at the same time, we sometimes encounter
interleaving in the middle of a line:
init[1]: segfault (11) at 0 nip 0 lr 0 code 1
init[1]: code: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
init[74]: segfault (11) at 10a74 nip 1000c198 lr 100078c8 code 1 in sh[10000000+14000]
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
init[1]: code: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
init[74]: code: 90010024 bf61000c 91490a7c 3fa01002 3be00000 7d3e4b78 3bbd0c20 3b600000
init[74]: code: 3b9d0040 7c7fe02e 2f830000 419e0028 <89230000> 2f890000 41be001c 4b7f6e79
This patch fixes it by preparing complete lines in a buffer and
printing it at once.
Fixes: 88b0fe1757359 ("powerpc: Add show_user_instructions()")
Reviewed-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Use seq_buf_printf() not seq_buf_puts() which doesn't NULL terminate]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 37 |
1 files changed, 19 insertions, 18 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 3396c419abf2..050f1136f587 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -43,6 +43,7 @@ #include <linux/uaccess.h> #include <linux/elf-randomize.h> #include <linux/pkeys.h> +#include <linux/seq_buf.h> #include <asm/pgtable.h> #include <asm/io.h> @@ -1300,7 +1301,9 @@ static void show_instructions(struct pt_regs *regs) void show_user_instructions(struct pt_regs *regs) { unsigned long pc; - int i; + int n = instructions_to_print; + struct seq_buf s; + char buf[96]; /* enough for 8 times 9 + 2 chars */ pc = regs->nip - (instructions_to_print * 3 / 4 * sizeof(int)); @@ -1314,29 +1317,27 @@ void show_user_instructions(struct pt_regs *regs) return; } - pr_info("%s[%d]: code: ", current->comm, current->pid); + seq_buf_init(&s, buf, sizeof(buf)); - for (i = 0; i < instructions_to_print; i++) { - int instr; + while (n) { + int i; - if (!(i % 8) && (i > 0)) { - pr_cont("\n"); - pr_info("%s[%d]: code: ", current->comm, current->pid); - } + seq_buf_clear(&s); - if (probe_kernel_address((const void *)pc, instr)) { - pr_cont("XXXXXXXX "); - } else { - if (regs->nip == pc) - pr_cont("<%08x> ", instr); - else - pr_cont("%08x ", instr); + for (i = 0; i < 8 && n; i++, n--, pc += sizeof(int)) { + int instr; + + if (probe_kernel_address((const void *)pc, instr)) { + seq_buf_printf(&s, "XXXXXXXX "); + continue; + } + seq_buf_printf(&s, regs->nip == pc ? "<%08x> " : "%08x ", instr); } - pc += sizeof(int); + if (!seq_buf_has_overflowed(&s)) + pr_info("%s[%d]: code: %s\n", current->comm, + current->pid, s.buffer); } - - pr_cont("\n"); } struct regbit { |