From 399d80ba8c604d57e7df6c5118ea3258cce026d9 Mon Sep 17 00:00:00 2001
From: Anita Zhang <the.anitazha@gmail.com>
Date: Mon, 8 Mar 2021 10:51:12 -0800
Subject: [PATCH 1/3] oomd: add unit test to repro #18926

---
 src/oom/test-oomd-util.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/oom/test-oomd-util.c b/src/oom/test-oomd-util.c
index a0e583ac6b..0b1a3adfcc 100644
--- a/src/oom/test-oomd-util.c
+++ b/src/oom/test-oomd-util.c
@@ -150,6 +150,7 @@ static void test_oomd_cgroup_context_acquire_and_insert(void) {
         assert_se(oomd_insert_cgroup_context(NULL, h1, cgroup) == 0);
         c1 = hashmap_get(h1, cgroup);
         assert_se(c1);
+        assert_se(oomd_insert_cgroup_context(NULL, h1, cgroup) == -EEXIST);
 
          /* make sure certain values from h1 get updated in h2 */
         c1->pgscan = 5555;

From 45da27fa053898c1b94c175070a0dd63128875c9 Mon Sep 17 00:00:00 2001
From: Anita Zhang <the.anitazha@gmail.com>
Date: Mon, 8 Mar 2021 10:35:31 -0800
Subject: [PATCH 2/3] oomd: move TAKE_PTR to end of
 oomd_insert_cgroup_context()

Fixes #18926
---
 src/oom/oomd-util.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/oom/oomd-util.c b/src/oom/oomd-util.c
index b054ccacc4..82bc9e2529 100644
--- a/src/oom/oomd-util.c
+++ b/src/oom/oomd-util.c
@@ -384,7 +384,7 @@ int oomd_system_context_acquire(const char *proc_swaps_path, OomdSystemContext *
 
 int oomd_insert_cgroup_context(Hashmap *old_h, Hashmap *new_h, const char *path) {
         _cleanup_(oomd_cgroup_context_freep) OomdCGroupContext *curr_ctx = NULL;
-        OomdCGroupContext *old_ctx, *ctx;
+        OomdCGroupContext *old_ctx;
         int r;
 
         assert(new_h);
@@ -401,11 +401,11 @@ int oomd_insert_cgroup_context(Hashmap *old_h, Hashmap *new_h, const char *path)
                 curr_ctx->last_hit_mem_pressure_limit = old_ctx->last_hit_mem_pressure_limit;
         }
 
-        ctx = TAKE_PTR(curr_ctx);
-        r = hashmap_put(new_h, ctx->path, ctx);
+        r = hashmap_put(new_h, curr_ctx->path, curr_ctx);
         if (r < 0)
                 return r;
 
+        TAKE_PTR(curr_ctx);
         return 0;
 }
 

From 50c0578b619e7298375afdffec7a8b3a40a68c21 Mon Sep 17 00:00:00 2001
From: Anita Zhang <the.anitazha@gmail.com>
Date: Mon, 8 Mar 2021 10:21:37 -0800
Subject: [PATCH 3/3] oomd: wrap paths in oomd_insert_cgroup_context with
 empty_to_root

---
 src/oom/oomd-manager.c | 2 +-
 src/oom/oomd-util.c    | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/oom/oomd-manager.c b/src/oom/oomd-manager.c
index fad1fb0d45..085fc6487f 100644
--- a/src/oom/oomd-manager.c
+++ b/src/oom/oomd-manager.c
@@ -112,7 +112,7 @@ static int process_managed_oom_reply(
                                 continue;
                 }
 
-                ret = oomd_insert_cgroup_context(NULL, monitor_hm, empty_to_root(reply.path));
+                ret = oomd_insert_cgroup_context(NULL, monitor_hm, reply.path);
                 if (ret == -ENOMEM) {
                         r = ret;
                         goto finish;
diff --git a/src/oom/oomd-util.c b/src/oom/oomd-util.c
index 82bc9e2529..d8dbb75013 100644
--- a/src/oom/oomd-util.c
+++ b/src/oom/oomd-util.c
@@ -390,10 +390,14 @@ int oomd_insert_cgroup_context(Hashmap *old_h, Hashmap *new_h, const char *path)
         assert(new_h);
         assert(path);
 
+        path = empty_to_root(path);
+
         r = oomd_cgroup_context_acquire(path, &curr_ctx);
         if (r < 0)
                 return log_debug_errno(r, "Failed to get OomdCGroupContext for %s: %m", path);
 
+        assert_se(streq(path, curr_ctx->path));
+
         old_ctx = hashmap_get(old_h, path);
         if (old_ctx) {
                 curr_ctx->last_pgscan = old_ctx->pgscan;