Messages in this thread Patch in this message | | | From | Christophe Leroy <> | Subject | [PATCH 1/2] powerpc/process: fix nested output in show_user_instructions() | Date | Tue, 14 Aug 2018 08:59:18 +0000 (UTC) |
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When two processes crash at the same time, we sometimes encounter nesting in the middle of a line:
[ 4.365317] init[1]: segfault (11) at 0 nip 0 lr 0 code 1 [ 4.370452] init[1]: code: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX [ 4.372042] init[74]: segfault (11) at 10a74 nip 1000c198 lr 100078c8 code 1 in sh[10000000+14000] [ 4.386829] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX [ 4.391542] init[1]: code: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX [ 4.400863] init[74]: code: 90010024 bf61000c 91490a7c 3fa01002 3be00000 7d3e4b78 3bbd0c20 3b600000 [ 4.409867] 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()") Cc: Murilo Opsfelder Araujo <muriloo@linux.ibm.com> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/kernel/process.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 913c5725cdb2..c722ce4ca1c0 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1303,32 +1303,33 @@ void show_user_instructions(struct pt_regs *regs) { unsigned long pc; int i; + char buf[96]; /* enough for 8 times 9 + 2 chars */ + int l = 0; pc = regs->nip - (instructions_to_print * 3 / 4 * sizeof(int)); - pr_info("%s[%d]: code: ", current->comm, current->pid); - for (i = 0; i < instructions_to_print; i++) { int instr; if (!(i % 8) && (i > 0)) { - pr_cont("\n"); - pr_info("%s[%d]: code: ", current->comm, current->pid); + pr_info("%s[%d]: code: %s\n", current->comm, current->pid, buf); + l = 0; } if (probe_kernel_address((unsigned int __user *)pc, instr)) { - pr_cont("XXXXXXXX "); + l += sprintf(buf + l, "XXXXXXXX "); } else { if (regs->nip == pc) - pr_cont("<%08x> ", instr); + l += sprintf(buf + l, "<%08x> ", instr); else - pr_cont("%08x ", instr); + l += sprintf(buf + l, "%08x ", instr); } pc += sizeof(int); } - pr_cont("\n"); + if (l) + pr_info("%s[%d]: code: %s\n", current->comm, current->pid, buf); } struct regbit { -- 2.13.3
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