Ye Bin (4): tracing/probes: support '%pd' type for print struct dentry's name tracing/probes: support '%pD' type for print struct file's name Documentation: tracing: add new type '%pd' and '%pD' for kprobe selftests/ftrace: add kprobe test cases for VFS type "%pd" and "%pD"
Documentation/trace/kprobetrace.rst | 7 +- kernel/trace/trace.c | 2 +- kernel/trace/trace_kprobe.c | 6 ++ kernel/trace/trace_probe.c | 64 +++++++++++++++++++ kernel/trace/trace_probe.h | 2 + .../ftrace/test.d/kprobe/kprobe_args_vfs.tc | 40 ++++++++++++ 6 files changed, 118 insertions(+), 3 deletions(-) create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc
mainline inclusion from mainline-v6.10-rc1 commit d9b15224dd8ff83b2aef87e4cd5ad10c875ef7d6 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAMXDU
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
During fault locating, the file name needs to be printed based on the dentry address. The offset needs to be calculated each time, which is troublesome. Similar to printk, kprobe support print type '%pd' for print dentry's name. For example "name=$arg1:%pd" casts the `$arg1` as (struct dentry *), dereferences the "d_name.name" field and stores it to "name" argument as a kernel string. Here is an example: [tracing]# echo 'p:testprobe dput name=$arg1:%pd' > kprobe_events [tracing]# echo 1 > events/kprobes/testprobe/enable [tracing]# grep -q "1" events/kprobes/testprobe/enable [tracing]# echo 0 > events/kprobes/testprobe/enable [tracing]# cat trace | grep "enable" bash-14844 [002] ..... 16912.889543: testprobe: (dput+0x4/0x30) name="enable" grep-15389 [003] ..... 16922.834182: testprobe: (dput+0x4/0x30) name="enable" grep-15389 [003] ..... 16922.836103: testprobe: (dput+0x4/0x30) name="enable" bash-14844 [001] ..... 16931.820909: testprobe: (dput+0x4/0x30) name="enable"
Note that this expects the given argument (e.g. $arg1) is an address of struct dentry. User must ensure it.
Link: https://lore.kernel.org/all/20240322064308.284457-2-yebin10@huawei.com/
Signed-off-by: Ye Bin yebin10@huawei.com Acked-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Masami Hiramatsu (Google) mhiramat@kernel.org Conflicts: kernel/trace/trace.c kernel/trace/trace_kprobe.c kernel/trace/trace_probe.c kernel/trace/trace_probe.h kernel/trace/trace_fprobe.c [Fix context diff] Signed-off-by: Ye Bin yebin10@huawei.com --- kernel/trace/trace.c | 2 +- kernel/trace/trace_kprobe.c | 6 +++++ kernel/trace/trace_probe.c | 50 +++++++++++++++++++++++++++++++++++++ kernel/trace/trace_probe.h | 2 ++ 4 files changed, 59 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a5a229d47fde..7d7418781fba 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5284,7 +5284,7 @@ static const char readme_msg[] = "\t +|-[u]<offset>(<fetcharg>), \imm-value, \"imm-string"\n" "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n" "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n" - "\t <type>\[<array-size>\]\n" + "\t %pd, <type>\[<array-size>\]\n" #ifdef CONFIG_HIST_TRIGGERS "\t field: <stype> <name>;\n" "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n" diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 0aff8c7a550e..de495a2951fb 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -750,6 +750,7 @@ static int trace_kprobe_create(int argc, const char *argv[]) long offset = 0; void *addr = NULL; char buf[MAX_EVENT_NAME_LEN]; + char *dbuf = NULL; unsigned int flags = TPARG_FL_KERNEL;
switch (argv[0][0]) { @@ -860,6 +861,10 @@ static int trace_kprobe_create(int argc, const char *argv[]) event = buf; }
+ ret = traceprobe_expand_dentry_args(argc, argv, &dbuf); + if (ret) + goto out; + /* setup a probe */ tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, argc - 2, is_return); @@ -905,6 +910,7 @@ static int trace_kprobe_create(int argc, const char *argv[]) out: trace_probe_log_clear(); kfree(symbol); + kfree(dbuf); return ret;
parse_error: diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 073abbe3866b..aafa3aa41d6e 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -803,6 +803,56 @@ void traceprobe_free_probe_arg(struct probe_arg *arg) kfree(arg->fmt); }
+/* @buf: *buf must be equal to NULL. Caller must to free *buf */ +int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf) +{ + int i, used, ret; + const int bufsize = MAX_DENTRY_ARGS_LEN; + char *tmpbuf = NULL; + + if (*buf) + return -EINVAL; + + used = 0; + for (i = 0; i < argc; i++) { + if (glob_match("*:%pd", argv[i])) { + char *tmp; + char *equal; + + if (!tmpbuf) { + tmpbuf = kmalloc(bufsize, GFP_KERNEL); + if (!tmpbuf) + return -ENOMEM; + } + + tmp = kstrdup(argv[i], GFP_KERNEL); + if (!tmp) + goto nomem; + + equal = strchr(tmp, '='); + if (equal) + *equal = '\0'; + tmp[strlen(argv[i]) - 4] = '\0'; + ret = snprintf(tmpbuf + used, bufsize - used, + "%s%s+0x0(+0x%zx(%s)):string", + equal ? tmp : "", equal ? "=" : "", + offsetof(struct dentry, d_name.name), + equal ? equal + 1 : tmp); + kfree(tmp); + if (ret >= bufsize - used) + goto nomem; + argv[i] = tmpbuf + used; + used += ret + 1; + } + } + + *buf = tmpbuf; + return 0; +nomem: + kfree(tmpbuf); + return -ENOMEM; +} + int traceprobe_update_arg(struct probe_arg *arg) { struct fetch_insn *code = arg->code; diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index d4a69b83902e..cc27f25ce77e 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -32,6 +32,7 @@ #define MAX_ARGSTR_LEN 63 #define MAX_ARRAY_LEN 64 #define MAX_ARG_NAME_LEN 32 +#define MAX_DENTRY_ARGS_LEN 256 #define MAX_STRING_SIZE PATH_MAX
/* Reserved field names */ @@ -355,6 +356,7 @@ bool trace_probe_match_command_args(struct trace_probe *tp, extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, char *arg, unsigned int flags);
+extern int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf); extern int traceprobe_update_arg(struct probe_arg *arg); extern void traceprobe_free_probe_arg(struct probe_arg *arg);
mainline inclusion from mainline-v6.10-rc1 commit 20fe4d07bde67ec26716835b61be2c4eeca1c6bc category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAMXDU
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
As like '%pd' type, this patch supports print type '%pD' for print file's name. For example "name=$arg1:%pD" casts the `$arg1` as (struct file*), dereferences the "file.f_path.dentry.d_name.name" field and stores it to "name" argument as a kernel string. Here is an example: [tracing]# echo 'p:testprobe vfs_read name=$arg1:%pD' > kprobe_event [tracing]# echo 1 > events/kprobes/testprobe/enable [tracing]# grep -q "1" events/kprobes/testprobe/enable [tracing]# echo 0 > events/kprobes/testprobe/enable [tracing]# grep "vfs_read" trace | grep "enable" grep-15108 [003] ..... 5228.328609: testprobe: (vfs_read+0x4/0xbb0) name="enable"
Note that this expects the given argument (e.g. $arg1) is an address of struct file. User must ensure it.
Link: https://lore.kernel.org/all/20240322064308.284457-3-yebin10@huawei.com/ [Masami: replaced "previous patch" with '%pd' type]
Signed-off-by: Ye Bin yebin10@huawei.com Acked-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Masami Hiramatsu (Google) mhiramat@kernel.org Conflicts: kernel/trace/trace.c kernel/trace/trace_probe.c [Fix context diff] Signed-off-by: Ye Bin yebin10@huawei.com --- kernel/trace/trace.c | 2 +- kernel/trace/trace_probe.c | 58 +++++++++++++++++++++++--------------- 2 files changed, 37 insertions(+), 23 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7d7418781fba..3c776919305a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5284,7 +5284,7 @@ static const char readme_msg[] = "\t +|-[u]<offset>(<fetcharg>), \imm-value, \"imm-string"\n" "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n" "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n" - "\t %pd, <type>\[<array-size>\]\n" + "\t %pd/%pD, <type>\[<array-size>\]\n" #ifdef CONFIG_HIST_TRIGGERS "\t field: <stype> <name>;\n" "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n" diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index aafa3aa41d6e..2b309dfc5b7f 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -11,6 +11,8 @@ */ #define pr_fmt(fmt) "trace_probe: " fmt
+#include <linux/fs.h> + #include "trace_probe.h"
#undef C @@ -815,35 +817,47 @@ int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
used = 0; for (i = 0; i < argc; i++) { - if (glob_match("*:%pd", argv[i])) { - char *tmp; - char *equal; - - if (!tmpbuf) { - tmpbuf = kmalloc(bufsize, GFP_KERNEL); - if (!tmpbuf) - return -ENOMEM; - } + char *tmp; + char *equal; + size_t arg_len; + + if (!glob_match("*:%p[dD]", argv[i])) + continue; + + if (!tmpbuf) { + tmpbuf = kmalloc(bufsize, GFP_KERNEL); + if (!tmpbuf) + return -ENOMEM; + }
- tmp = kstrdup(argv[i], GFP_KERNEL); - if (!tmp) - goto nomem; + tmp = kstrdup(argv[i], GFP_KERNEL); + if (!tmp) + goto nomem;
- equal = strchr(tmp, '='); - if (equal) - *equal = '\0'; - tmp[strlen(argv[i]) - 4] = '\0'; + equal = strchr(tmp, '='); + if (equal) + *equal = '\0'; + arg_len = strlen(argv[i]); + tmp[arg_len - 4] = '\0'; + if (argv[i][arg_len - 1] == 'd') ret = snprintf(tmpbuf + used, bufsize - used, "%s%s+0x0(+0x%zx(%s)):string", equal ? tmp : "", equal ? "=" : "", offsetof(struct dentry, d_name.name), equal ? equal + 1 : tmp); - kfree(tmp); - if (ret >= bufsize - used) - goto nomem; - argv[i] = tmpbuf + used; - used += ret + 1; - } + else + ret = snprintf(tmpbuf + used, bufsize - used, + "%s%s+0x0(+0x%zx(+0x%zx(%s))):string", + equal ? tmp : "", equal ? "=" : "", + offsetof(struct dentry, d_name.name), + offsetof(struct file, f_path.dentry), + equal ? equal + 1 : tmp); + + kfree(tmp); + if (ret >= bufsize - used) + goto nomem; + argv[i] = tmpbuf + used; + used += ret + 1; }
*buf = tmpbuf;
mainline inclusion from mainline-v6.10-rc1 commit 5e37460f5f9266bcd037137f1bd9eb24b9940faf category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAMXDU
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
Similar to printk() '%pd' is for fetch dentry's name from struct dentry's pointer, and '%pD' is for fetch file's name from struct file's pointer.
Link: https://lore.kernel.org/all/20240322064308.284457-4-yebin10@huawei.com/
Signed-off-by: Ye Bin yebin10@huawei.com Acked-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Masami Hiramatsu (Google) mhiramat@kernel.org Conflicts: Documentation/trace/kprobetrace.rst [Fix context diff] Signed-off-by: Ye Bin yebin10@huawei.com --- Documentation/trace/kprobetrace.rst | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst index b175d88f31eb..0f17078a18a5 100644 --- a/Documentation/trace/kprobetrace.rst +++ b/Documentation/trace/kprobetrace.rst @@ -58,8 +58,8 @@ Synopsis of kprobe_events NAME=FETCHARG : Set NAME as the argument name of FETCHARG. FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types - (x8/x16/x32/x64), "string", "ustring" and bitfield - are supported. + (x8/x16/x32/x64), VFS layer common type(%pd/%pD), + "string", "ustring" and bitfield are supported.
(*1) only for the probe on function entry (offs == 0). (*2) only for return probe. @@ -98,6 +98,9 @@ Symbol type('symbol') is an alias of u32 or u64 type (depends on BITS_PER_LONG) which shows given pointer in "symbol+offset" style. For $comm, the default type is "string"; any other type is invalid.
+VFS layer common type(%pd/%pD) is a special type, which fetches dentry's or +file's name from struct dentry's address or struct file's address. + .. _user_mem_access:
User Memory Access
mainline inclusion from mainline-v6.10-rc1 commit c01768b05e306d8c8d5997356ff427f5d53c7d20 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAMXDU
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
This patch adds test cases for new print format type "%pd/%pD".The test cases test the following items: 1. Test README if add "%pd/%pD" type; 2. Test "%pd" type for dput(); 3. Test "%pD" type for vfs_read();
This test case require enable CONFIG_HAVE_FUNCTION_ARG_ACCESS_API configuration.
Link: https://lore.kernel.org/all/20240322064308.284457-5-yebin10@huawei.com/
Signed-off-by: Ye Bin yebin10@huawei.com Acked-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Ye Bin yebin10@huawei.com --- .../ftrace/test.d/kprobe/kprobe_args_vfs.tc | 40 +++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc new file mode 100644 index 000000000000..21a54be6894c --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_vfs.tc @@ -0,0 +1,40 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Kprobe event VFS type argument +# requires: kprobe_events "%pd/%pD":README + +: "Test argument %pd with name" +echo 'p:testprobe dput name=$arg1:%pd' > kprobe_events +echo 1 > events/kprobes/testprobe/enable +grep -q "1" events/kprobes/testprobe/enable +echo 0 > events/kprobes/testprobe/enable +grep "dput" trace | grep -q "enable" +echo "" > kprobe_events +echo "" > trace + +: "Test argument %pd without name" +echo 'p:testprobe dput $arg1:%pd' > kprobe_events +echo 1 > events/kprobes/testprobe/enable +grep -q "1" events/kprobes/testprobe/enable +echo 0 > events/kprobes/testprobe/enable +grep "dput" trace | grep -q "enable" +echo "" > kprobe_events +echo "" > trace + +: "Test argument %pD with name" +echo 'p:testprobe vfs_read name=$arg1:%pD' > kprobe_events +echo 1 > events/kprobes/testprobe/enable +grep -q "1" events/kprobes/testprobe/enable +echo 0 > events/kprobes/testprobe/enable +grep "vfs_read" trace | grep -q "enable" +echo "" > kprobe_events +echo "" > trace + +: "Test argument %pD without name" +echo 'p:testprobe vfs_read $arg1:%pD' > kprobe_events +echo 1 > events/kprobes/testprobe/enable +grep -q "1" events/kprobes/testprobe/enable +echo 0 > events/kprobes/testprobe/enable +grep "vfs_read" trace | grep -q "enable" +echo "" > kprobe_events +echo "" > trace
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