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Diffstat (limited to 'meta-networking/recipes-netkit/netkit-telnet/files/0001-telnet-telnetd-Fix-deadlock-on-cleanup.patch')
| -rw-r--r-- | meta-networking/recipes-netkit/netkit-telnet/files/0001-telnet-telnetd-Fix-deadlock-on-cleanup.patch | 114 |
1 files changed, 0 insertions, 114 deletions
diff --git a/meta-networking/recipes-netkit/netkit-telnet/files/0001-telnet-telnetd-Fix-deadlock-on-cleanup.patch b/meta-networking/recipes-netkit/netkit-telnet/files/0001-telnet-telnetd-Fix-deadlock-on-cleanup.patch deleted file mode 100644 index 945785d3ce..0000000000 --- a/meta-networking/recipes-netkit/netkit-telnet/files/0001-telnet-telnetd-Fix-deadlock-on-cleanup.patch +++ /dev/null @@ -1,114 +0,0 @@ -From 06ed6a6bf25a22902846097d6b6c97e070c2c326 Mon Sep 17 00:00:00 2001 -From: Seiichi Ishitsuka <ishitsuka.sc@ncos.nec.co.jp> -Date: Fri, 1 Jun 2018 14:27:35 +0900 -Subject: [PATCH] telnetd: Fix deadlock on cleanup - -The cleanup function in telnetd is called both directly and on SIGCHLD -signals. This, unfortunately, triggered a deadlock in eglibc 2.9 while -running on a 2.6.31.11 kernel. - -What we were seeing is hangs like these: - - (gdb) bt - #0 0xb7702424 in __kernel_vsyscall () - #1 0xb7658e61 in __lll_lock_wait_private () from ./lib/libc.so.6 - #2 0xb767e7b5 in _L_lock_15 () from ./lib/libc.so.6 - #3 0xb767e6e0 in utmpname () from ./lib/libc.so.6 - #4 0xb76bcde7 in logout () from ./lib/libutil.so.1 - #5 0x0804c827 in cleanup () - #6 <signal handler called> - #7 0xb7702424 in __kernel_vsyscall () - #8 0xb7641003 in __fcntl_nocancel () from ./lib/libc.so.6 - #9 0xb767e0c3 in getutline_r_file () from ./lib/libc.so.6 - #10 0xb767d675 in getutline_r () from ./lib/libc.so.6 - #11 0xb76bce42 in logout () from ./lib/libutil.so.1 - #12 0x0804c827 in cleanup () - #13 0x0804a0b5 in telnet () - #14 0x0804a9c3 in main () - -and what has happened here is that the user closes the telnet session -via the escape character. This causes telnetd to call cleanup in frame -the SIGCHLD signal is delivered while telnetd is executing cleanup. - -Telnetd then calls the signal handler for SIGCHLD, which is cleanup(). -Ouch. The actual deadlock is in libc. getutline_r in frame #10 gets the -__libc_utmp_lock lock, and utmpname above does the same thing in frame - -The fix registers the SIGCHLD handler as cleanup_sighandler, and makes -cleanup disable the SIGCHLD signal before calling cleanup_sighandler. - -Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net> - -The patch was imported from the Ubuntu netkit-telnet package. -(https://bugs.launchpad.net/ubuntu/+source/netkit-telnet/+bug/507455) - -A previous patch declaring attributes of functions, but it is not used -in upstream. - -Signed-off-by: Seiichi Ishitsuka <ishitsuka.sc@ncos.nec.co.jp> ---- - telnetd/ext.h | 1 + - telnetd/sys_term.c | 17 ++++++++++++++++- - telnetd/telnetd.c | 2 +- - 3 files changed, 18 insertions(+), 2 deletions(-) - -diff --git a/telnetd/ext.h b/telnetd/ext.h -index b98d6ec..08f9d07 100644 ---- a/telnetd/ext.h -+++ b/telnetd/ext.h -@@ -97,6 +97,7 @@ void add_slc(int, int, int); - void check_slc(void); - void change_slc(int, int, int); - void cleanup(int); -+void cleanup_sighandler(int); - void clientstat(int, int, int); - void copy_termbuf(char *, int); - void deferslc(void); -diff --git a/telnetd/sys_term.c b/telnetd/sys_term.c -index 5b4aa84..c4fb0f7 100644 ---- a/telnetd/sys_term.c -+++ b/telnetd/sys_term.c -@@ -719,7 +719,7 @@ static void addarg(struct argv_stuff *avs, const char *val) { - * This is the routine to call when we are all through, to - * clean up anything that needs to be cleaned up. - */ --void cleanup(int sig) { -+void cleanup_sighandler(int sig) { - char *p; - (void)sig; - -@@ -742,3 +742,18 @@ void cleanup(int sig) { - shutdown(net, 2); - exit(0); - } -+ -+void cleanup(int sig) { -+ sigset_t mask, oldmask; -+ -+ /* Set up the mask of signals to temporarily block. */ -+ sigemptyset (&mask); -+ sigaddset (&mask, SIGCHLD); -+ -+ /* Block SIGCHLD while running cleanup */ -+ sigprocmask (SIG_BLOCK, &mask, &oldmask); -+ -+ cleanup_sighandler(sig); -+ /* Technically not needed since cleanup_sighandler exits */ -+ sigprocmask (SIG_UNBLOCK, &mask, NULL); -+} -diff --git a/telnetd/telnetd.c b/telnetd/telnetd.c -index 9ace838..788919c 100644 ---- a/telnetd/telnetd.c -+++ b/telnetd/telnetd.c -@@ -833,7 +833,7 @@ void telnet(int f, int p) - signal(SIGTTOU, SIG_IGN); - #endif - -- signal(SIGCHLD, cleanup); -+ signal(SIGCHLD, cleanup_sighandler); - - #ifdef TIOCNOTTY - { --- -2.7.4 - |