diff options
author | Lubomir Rintel <lkundrak@v3.sk> | 2022-10-10 18:37:31 +0200 |
---|---|---|
committer | Jiri Pirko <jiri@nvidia.com> | 2022-11-24 15:44:12 +0100 |
commit | ffc6a52bd285a476b547312012078af69220574b (patch) | |
tree | c63cd1600cfcb70866b65ac6b844fbdbc7f2e217 | |
parent | dbb2cfca35d2cd15125eb84e8f3940f8cc3ea860 (diff) | |
download | libteam-ffc6a52bd285a476b547312012078af69220574b.tar.gz |
teamd: stop iterating callbacks when a loop restart is requested
A crash was observed:
Added loop callback: dbus_watch, 0x560d279e4530
Added loop callback: dbus_watch, 0x560d279e4580
...
Removed loop callback: dbus_watch, 0x560d279e4580
Removed loop callback: dbus_watch, 0x560d279e4530
Aug 31 11:54:11 holaprdel kernel: traps: teamd[557] general protection fault ip:560d26469a55 sp:7ffd43ca9650 error:0 in teamd[560d26463000+16000]
Traceback (from a different run than above):
Core was generated by `/usr/bin/teamd -o -n -U -D -N -t team0 -gg'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x00005600ac090a55 in teamd_run_loop_do_callbacks (ctx=0x5600ad9bac70, fds=0x7fff40861250, lcb_list=0x5600ad9bad58) at /usr/src/debug/libteam-1.31-14.el9.x86_64/teamd/teamd.c:321
321 list_for_each_node_entry_safe(lcb, tmp, lcb_list, list) {
(gdb) bt
#0 0x00005600ac090a55 in teamd_run_loop_do_callbacks (ctx=0x5600ad9bac70, fds=0x7fff40861250, lcb_list=0x5600ad9bad58) at /usr/src/debug/libteam-1.31-14.el9.x86_64/teamd/teamd.c:321
#1 teamd_run_loop_run (ctx=0x5600ad9bac70) at /usr/src/debug/libteam-1.31-14.el9.x86_64/teamd/teamd.c:415
#2 0x00005600ac08d8cb in teamd_start (p_ret=<synthetic pointer>, ctx=<optimized out>) at /usr/src/debug/libteam-1.31-14.el9.x86_64/teamd/teamd.c:1557
#3 main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/libteam-1.31-14.el9.x86_64/teamd/teamd.c:1876
(gdb) print *lcb
Cannot access memory at address 0x9dd29944fb7e97fc
(gdb) print *tmp
Cannot access memory at address 0x9dd29944fb7e9804
(gdb)
What has happened is that libdbus called the remove_watch callback twice
in a single go, causing two callbacks being destroyed in one iteration
of teamd_run_loop_do_callbacks()'s list_for_each_node_entry_safe().
This basically turns the _safe() variant of the macro unhelpful, as tmp
points to stale data anyway.
Let's use the unsafe variant then, and terminate the loop once
teamd_loop_callback_del() asks for main loop's attention via
teamd_run_loop_restart(). If there are other callbacks pending an action,
they will get their turn in the next main loop iteration.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
-rw-r--r-- | teamd/teamd.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/teamd/teamd.c b/teamd/teamd.c index b310140..a89b702 100644 --- a/teamd/teamd.c +++ b/teamd/teamd.c @@ -309,16 +309,28 @@ static void teamd_run_loop_set_fds(struct list_item *lcb_list, } } +static int teamd_check_ctrl(struct teamd_context *ctx) +{ + int ctrl_fd = ctx->run_loop.ctrl_pipe_r; + struct timeval tv; + fd_set rfds; + + FD_ZERO(&rfds); + FD_SET(ctrl_fd, &rfds); + tv.tv_sec = tv.tv_usec = 0; + + return select(ctrl_fd + 1, &rfds, NULL, NULL, &tv); +} + static int teamd_run_loop_do_callbacks(struct list_item *lcb_list, fd_set *fds, struct teamd_context *ctx) { struct teamd_loop_callback *lcb; - struct teamd_loop_callback *tmp; int i; int events; int err; - list_for_each_node_entry_safe(lcb, tmp, lcb_list, list) { + list_for_each_node_entry(lcb, lcb_list, list) { for (i = 0; i < 3; i++) { if (!(lcb->fd_event & (1 << i))) continue; @@ -339,6 +351,16 @@ static int teamd_run_loop_do_callbacks(struct list_item *lcb_list, fd_set *fds, teamd_log_dbg(ctx, "Failed loop callback: %s, %p", lcb->name, lcb->priv); } + + /* + * If there's a control byte ready, it's possible that + * one or more entries have been removed from the + * callback list and restart has been requested. In any + * case, let the main loop deal with it first so that + * we know we're safe to proceed. + */ + if (teamd_check_ctrl(ctx)) + return 0; } } return 0; |