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Subject[PATCH] fs/resctrl: fix domid loss precision issue
Date
Below statement from mkdir_mondata_subdir function will loss precision,
because it assigns int to 14 bits bitfield.
priv.u.domid = d->id;

This will cause below issue if cache_id > 0x3fff likes:
/sys/fs/resctrl/mon_groups/p1/mon_data/mon_L3_1048564 # cat llc_occupancy
cat: read error: No such file or directory

This is the call trace when cat llc_occupancy:
rdtgroup_mondata_show()
domid = md.u.domid
d = resctrl_arch_find_domain(r, domid)

d is null here because of lossing precision

Signed-off-by: Rex Nie <rex.nie@jaguarmicro.com>
Signed-off-by: Liming Wu <liming.wu@jaguar.com>
---
fs/resctrl/internal.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 7a6f46b4edd0..096317610949 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -94,7 +94,7 @@ union mon_data_bits {
struct {
unsigned int rid : 10;
enum resctrl_event_id evtid : 8;
- unsigned int domid : 14;
+ u32 domid;
} u;
};

--
2.34.1

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