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lsmod, libkmod: handle module changes during execution #42

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lsmod, libkmod: handle module changes during execution #42

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2 changes: 1 addition & 1 deletion libkmod/libkmod-module.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2049,7 +2049,7 @@ KMOD_EXPORT int kmod_module_get_refcnt(const struct kmod_module *mod)
fd = open(path, O_RDONLY|O_CLOEXEC);
if (fd < 0) {
err = -errno;
DBG(mod->ctx, "could not open '%s': %s\n",
ERR(mod->ctx, "could not open '%s': %s\n",
path, strerror(errno));
return err;
}
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12 changes: 10 additions & 2 deletions tools/lsmod.c
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Original file line number Diff line number Diff line change
Expand Up @@ -61,11 +61,19 @@ static int do_lsmod(int argc, char *argv[])
const char *name = kmod_module_get_name(mod);
int use_count = kmod_module_get_refcnt(mod);
long size = kmod_module_get_size(mod);
struct kmod_list *holders, *hitr;
struct kmod_list *holders = kmod_module_get_holders(mod), *hitr;
int first = 1;

if (holders == NULL || use_count < 0 || size < 0) {
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holders == NULL is a normal thing to have, e.g:

serio_raw              20480  0

use_count < 0 allows us to use modules in the "going" state, i.e. in the process of being unloaded.

size < 0 I believe is the only one that we should really do something.... maybe setting it to 0. Rather than exiting here, I think we should just handle the races as a normal situation and continue printing the rest of the list.

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An illustration of negative use_count:

In a handful of instances (buggy/glitchy bluetooth + rmmod non-force) I have ended up with foobar 1234 -1. At which point the kernel(?) was completely foobar'd and reboot was needed.

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@SuibianP can you rebase taking this into account?

fprintf(stderr, "Error: could not query module %s! Was the module unloaded?\n", name);
kmod_module_unref_list(holders);
kmod_module_unref(mod);
kmod_module_unref_list(list);
kmod_unref(ctx);
return EXIT_FAILURE;
}

printf("%-19s %8ld %d", name, size, use_count);
holders = kmod_module_get_holders(mod);
kmod_list_foreach(hitr, holders) {
struct kmod_module *hm = kmod_module_get_module(hitr);

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