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authorDenys Vlasenko <vda.linux@googlemail.com>2020-09-29 16:44:46 +0200
committerDenys Vlasenko <vda.linux@googlemail.com>2020-09-29 20:21:27 +0200
commit8d5f465a206e307bc47d8157b6c90152ddd2ab3c (patch)
treeaa30fba353f4c4bed356c2772a28d73e8e815be4
parent777a6357c09e1e91acfde060144dd019e3baaf3c (diff)
downloadbusybox-8d5f465a206e307bc47d8157b6c90152ddd2ab3c.tar.gz
ash: jobs: Fix infinite loop in waitproc
Upstream commit: Date: Fri, 10 Apr 2020 21:03:09 +1000 jobs: Fix infinite loop in waitproc After we changed the resetting of gotsigchld so that it is only done if jp is NULL, we can now get an infinite loop in waitproc if gotsigchld is set but there is no outstanding child because everything had been waited for previously without gotsigchld being zeroed. This patch fixes it by always zeroing gotsigchld as we did before. The bug that the previous patch was trying to fix is now resolved by switching the blocking mode to DOWAIT_NORMAL after the specified job has been completed so that we really do wait for all outstanding dead children. Reported-by: Harald van Dijk <harald@gigawatt.nl> Fixes: 6c691b3e5099 ("jobs: Only clear gotsigchld when waiting...") Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> function old new delta dowait 553 631 +78 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--shell/ash.c25
1 files changed, 19 insertions, 6 deletions
diff --git a/shell/ash.c b/shell/ash.c
index ac25866ec..13470b2fa 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -4453,15 +4453,28 @@ waitone(int block, struct job *job)
static int
dowait(int block, struct job *jp)
{
- int pid = block == DOWAIT_NONBLOCK ? got_sigchld : 1;
+ smallint gotchld = *(volatile smallint *)&got_sigchld;
+ int rpid;
+ int pid;
+
+ if (jp && jp->state != JOBRUNNING)
+ block = DOWAIT_NONBLOCK;
+
+ if (block == DOWAIT_NONBLOCK && !gotchld)
+ return 1;
+
+ rpid = 1;
- while (jp ? jp->state == JOBRUNNING : pid > 0) {
- if (!jp)
- got_sigchld = 0;
+ do {
+ got_sigchld = 0;
pid = waitone(block, jp);
- }
+ rpid &= !!pid;
- return pid;
+ if (!pid || (jp && jp->state != JOBRUNNING))
+ block = DOWAIT_NONBLOCK;
+ } while (pid >= 0);
+
+ return rpid;
}
#if JOBS