From 7e7b7a1f427013374f38e1b101969a1dbce5c9c1 Mon Sep 17 00:00:00 2001 From: Reshma Pattan Date: Thu, 11 Apr 2019 12:13:36 +0100 Subject: [PATCH] examples/power: fix overflowed value Fix the data type of last_branches, last_branch_misses from uint32_t to uint64_t, and for hits_diff, miss_diff from int to int64_t respectively to fix possible overflow or truncation. Coverity issue: 337677 Fixes: 4b1a631b8a ("examples/vm_power: add oob monitoring functions") Cc: stable@dpdk.org Signed-off-by: Reshma Pattan Reviewed-by: Anatoly Burakov --- examples/vm_power_manager/oob_monitor_x86.c | 23 ++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/examples/vm_power_manager/oob_monitor_x86.c b/examples/vm_power_manager/oob_monitor_x86.c index 589c604e5c..ebd96b205f 100644 --- a/examples/vm_power_manager/oob_monitor_x86.c +++ b/examples/vm_power_manager/oob_monitor_x86.c @@ -33,10 +33,10 @@ static float apply_policy(int core) { struct core_info *ci; - uint64_t counter; + uint64_t counter = 0; uint64_t branches, branch_misses; - uint32_t last_branches, last_branch_misses; - int hits_diff, miss_diff; + uint64_t last_branches, last_branch_misses; + int64_t hits_diff, miss_diff; float ratio; int ret; @@ -54,6 +54,7 @@ apply_policy(int core) core); branches = counter; + counter = 0; ret = pread(ci->cd[core].msr_fd, &counter, sizeof(counter), IA32_PERFCTR1); if (ret < 0) @@ -66,13 +67,25 @@ apply_policy(int core) ci->cd[core].last_branches = branches; ci->cd[core].last_branch_misses = branch_misses; - hits_diff = (int)branches - (int)last_branches; + /* + * Intentional right shift to make MSB 0 to avoid + * possible signed overflow or truncation. + */ + branches >>= 1; + last_branches >>= 1; + hits_diff = (int64_t)branches - (int64_t)last_branches; if (hits_diff <= 0) { /* Likely a counter overflow condition, skip this round */ return -1.0; } - miss_diff = (int)branch_misses - (int)last_branch_misses; + /* + * Intentional right shift to make MSB 0 to avoid + * possible signed overflow or truncation. + */ + branch_misses >>= 1; + last_branch_misses >>= 1; + miss_diff = (int64_t)branch_misses - (int64_t)last_branch_misses; if (miss_diff <= 0) { /* Likely a counter overflow condition, skip this round */ return -1.0; -- 2.20.1