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Code Issues Releases Wiki Activity

Revert "tracing: Add "(fault)" name injection to kernel probes"

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[ Upstream commit 4ed8f337de ]

This reverts commit 2e9906f84f.

It was turned out that commit 2e9906f84f ("tracing: Add "(fault)"
name injection to kernel probes") did not work correctly and probe
events still show just '(fault)' (instead of '"(fault)"'). Also,
current '(fault)' is more explicit that it faulted.

This also moves FAULT_STRING macro to trace.h so that synthetic
event can keep using it, and uses it in trace_probe.c too.

Link: https://lore.kernel.org/all/168908495772.123124.1250788051922100079.stgit@devnote2/
Link: https://lore.kernel.org/all/20230706230642.3793a593@rorschach.local.home/

Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Stable-dep-of: 797311bce5 ("tracing/probes: Fix to record 0-length data_loc in fetch_store_string*() if fails")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Masami Hiramatsu (Google) 2023-07-11 23:15:57 +09:00 committed by Greg Kroah-Hartman
parent 5f52389bdd
commit 30c8ba1da3
3 changed files with 9 additions and 26 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
kernel/trace/trace.h
View file

@ -113,6 +113,8 @@ enum trace_type {
#define MEM_FAIL(condition, fmt, ...) \
DO_ONCE_LITE_IF(condition, pr_err, "ERROR: " fmt, ##__VA_ARGS__)
#define FAULT_STRING "(fault)"
#define HIST_STACKTRACE_DEPTH 16
#define HIST_STACKTRACE_SIZE (HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
#define HIST_STACKTRACE_SKIP 5

2
kernel/trace/trace_probe.c
View file

@ -64,7 +64,7 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
int len = *(u32 *)data >> 16;
if (!len)
trace_seq_puts(s, "(fault)");
trace_seq_puts(s, FAULT_STRING);
else
trace_seq_printf(s, "\"%s\"",
(const char *)get_loc_data(data, ent));

31
kernel/trace/trace_probe_kernel.h
View file

@ -2,8 +2,6 @@
#ifndef __TRACE_PROBE_KERNEL_H_
#define __TRACE_PROBE_KERNEL_H_
#define FAULT_STRING "(fault)"
/*
* This depends on trace_probe.h, but can not include it due to
* the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c.
@ -15,16 +13,8 @@ static nokprobe_inline int
kern_fetch_store_strlen_user(unsigned long addr)
{
const void __user *uaddr = (__force const void __user *)addr;
int ret;
ret = strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
/*
* strnlen_user_nofault returns zero on fault, insert the
* FAULT_STRING when that occurs.
*/
if (ret <= 0)
return strlen(FAULT_STRING) + 1;
return ret;
return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
}
/* Return the length of string -- including null terminal byte */
@ -44,18 +34,7 @@ kern_fetch_store_strlen(unsigned long addr)
len++;
} while (c && ret == 0 && len < MAX_STRING_SIZE);
/* For faults, return enough to hold the FAULT_STRING */
return (ret < 0) ? strlen(FAULT_STRING) + 1 : len;
}
static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base, int len)
{
if (ret >= 0) {
*(u32 *)dest = make_data_loc(ret, __dest - base);
} else {
strscpy(__dest, FAULT_STRING, len);
ret = strlen(__dest) + 1;
}
return (ret < 0) ? ret : len;
}
/*
@ -76,7 +55,8 @@ kern_fetch_store_string_user(unsigned long addr, void *dest, void *base)
__dest = get_loc_data(dest, base);
ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
set_data_loc(ret, dest, __dest, base, maxlen);
if (ret >= 0)
*(u32 *)dest = make_data_loc(ret, __dest - base);
return ret;
}
@ -107,7 +87,8 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base)
* probing.
*/
ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
set_data_loc(ret, dest, __dest, base, maxlen);
if (ret >= 0)
*(u32 *)dest = make_data_loc(ret, __dest - base);
return ret;
}