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[213.77.89.56]) by smtp.gmail.com with ESMTPSA id h2-20020a0564020e8200b005532a337d51sm3288494eda.44.2023.12.22.17.52.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Dec 2023 17:52:08 -0800 (PST) From: =?UTF-8?q?=C5=81ukasz=20Bartosik?= To: Jason Baron , Jim Cromie , Andrew Morton , Kees Cook , Douglas Anderson Cc: Guenter Roeck , Yaniv Tzoreff , Benson Leung , Steven Rostedt , Vincent Whitchurch , Pekka Paalanen , Sean Paul , Daniel Vetter , Simon Ser , John Ogness , Petr Mladek , Sergey Senozhatsky , linux-kernel@vger.kernel.org, upstream@semihalf.com Subject: [PATCH v3 11/22] dyndbg: don't close trace instance when in use Date: Sat, 23 Dec 2023 02:51:20 +0100 Message-ID: <20231223015131.2836090-12-lb@semihalf.com> X-Mailer: git-send-email 2.43.0.472.g3155946c3a-goog In-Reply-To: <20231223015131.2836090-1-lb@semihalf.com> References: <20231223015131.2836090-1-lb@semihalf.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Don't allow trace instance to be closed when it is still being used by at least one callsite. Signed-off-by: =C5=81ukasz Bartosik --- lib/dynamic_debug.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index dd4510ad124e..59682729ed3a 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -81,6 +81,7 @@ struct flag_settings { struct dd_private_tracebuf { const char *name; struct trace_array *arr; + int use_cnt; }; =20 /* @@ -279,6 +280,7 @@ static int handle_trace_open_cmd(const char *arg) goto end; } =20 + buf->use_cnt =3D 0; set_bit(idx, trc_tbl.bmap); v3pr_info("opened trace instance idx=3D%d, name=3D%s\n", idx, arg); end: @@ -301,6 +303,14 @@ static int handle_trace_close_cmd(const char *arg) =20 buf =3D &trc_tbl.buf[idx]; =20 + WARN_ON(buf->use_cnt < 0); + if (buf->use_cnt) { + pr_err("trace instance is being used name=3D%s, use_cnt=3D%d\n", + buf->name, buf->use_cnt); + ret =3D -EBUSY; + goto end; + } + trace_array_put(buf->arr); /* * don't destroy trace instance but let user do it manually @@ -321,6 +331,24 @@ static int handle_trace_close_cmd(const char *arg) return ret; } =20 +static +void update_tr_dst(const struct _ddebug *desc, const struct dd_ctrl *nctrl) +{ + int oflags =3D get_flags(desc), odst =3D get_trace_dst(desc); + int nflags =3D nctrl->flags, ndst =3D nctrl->trace_dst; + + if (oflags & _DPRINTK_FLAGS_TRACE && + nflags & _DPRINTK_FLAGS_TRACE && + odst =3D=3D ndst) + return; + + if (odst && (oflags & _DPRINTK_FLAGS_TRACE)) + trc_tbl.buf[odst].use_cnt--; + + if (ndst && (nflags & _DPRINTK_FLAGS_TRACE)) + trc_tbl.buf[ndst].use_cnt++; +} + static int ddebug_parse_cmd(char *words[], int nwords) { if (nwords !=3D 1) @@ -447,6 +475,7 @@ static int ddebug_change(const struct ddebug_query *que= ry, dt->mod_name, dp->function, ddebug_describe_flags(get_flags(dp), &fbuf), ddebug_describe_flags(nctrl.flags, &nbuf)); + update_tr_dst(dp, &nctrl); set_ctrl(dp, &nctrl); } } @@ -1628,6 +1657,15 @@ int ddebug_dyndbg_module_param_cb(char *param, char = *val, const char *module) =20 static void ddebug_table_free(struct ddebug_table *dt) { + + int dst, i; + + for (i =3D 0; i < dt->num_ddebugs; i++) { + dst =3D get_trace_dst(&dt->ddebugs[i]); + if (dst && (get_flags(&dt->ddebugs[i]) & _DPRINTK_FLAGS_TRACE)) + trc_tbl.buf[dst].use_cnt--; + } + list_del_init(&dt->link); kfree(dt); } --=20 2.43.0.472.g3155946c3a-goog