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| author | Denys Vlasenko <vda.linux@googlemail.com> | 2020-09-29 16:44:46 +0200 |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2020-09-29 20:21:27 +0200 |
| commit | 8d5f465a206e307bc47d8157b6c90152ddd2ab3c (patch) | |
| tree | aa30fba353f4c4bed356c2772a28d73e8e815be4 /shell | |
| parent | 777a6357c09e1e91acfde060144dd019e3baaf3c (diff) | |
| download | busybox-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>
Diffstat (limited to 'shell')
| -rw-r--r-- | shell/ash.c | 25 |
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 |