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    SubjectRe: [PATCH] iwlwifi: iwl-dbg: Use del_timer_sync() before freeing
    On Wed, Apr 13, 2022 at 11:56 AM Greenman, Gregory
    <gregory.greenman@intel.com> wrote:
    >
    >
    > On Mon, 2022-04-11 at 08:42 -0700, Guenter Roeck wrote:
    > > In Chrome OS, a large number of crashes is observed due to corrupted
    > > timer
    > > lists. Steven Rostedt pointed out that this usually happens when a
    > > timer
    > > is freed while still active, and that the problem is often triggered
    > > by code calling del_timer() instead of del_timer_sync() just before
    > > freeing.
    > >
    > > Steven also identified the iwlwifi driver as one of the possible
    > > culprits
    > > since it does exactly that.
    > >
    > > Reported-by: Steven Rostedt <rostedt@goodmis.org>
    > > Cc: Steven Rostedt <rostedt@goodmis.org>
    > > Cc: Johannes Berg <johannes.berg@intel.com>
    > > Cc: Gregory Greenman <gregory.greenman@intel.com>
    > > Fixes: 60e8abd9d3e91 ("iwlwifi: dbg_ini: add periodic trigger new API
    > > support")
    > > Signed-off-by: Guenter Roeck <linux@roeck-us.net>
    > > ---
    > > v1 (from RFC):
    > > Removed Shahar S Matityahu from Cc: and added Gregory Greenman.
    > > No functional change.
    > >
    > > I thought about the need to add a mutex to protect the timer list,
    > > but
    > > I convinced myself that it is not necessary because the code adding
    > > the timer list and the code removing it should never be never
    > > executed
    > > in parallel.
    > >
    > > drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c | 2 +-
    > > 1 file changed, 1 insertion(+), 1 deletion(-)
    > >
    > > diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
    > > b/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
    > > index 866a33f49915..3237d4b528b5 100644
    > > --- a/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
    > > +++ b/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
    > > @@ -371,7 +371,7 @@ void iwl_dbg_tlv_del_timers(struct iwl_trans
    > > *trans)
    > > struct iwl_dbg_tlv_timer_node *node, *tmp;
    > >
    > > list_for_each_entry_safe(node, tmp, timer_list, list) {
    > > - del_timer(&node->timer);
    > > + del_timer_sync(&node->timer);
    > > list_del(&node->list);
    > > kfree(node);
    > > }
    >
    > Hi Kalle,
    >
    > Can you please pick it up to wireless-drivers for the next rc?
    > It is an important fix.
    > Luca has already assigned it to you in patchwork.
    >
    > Thanks!
    >
    > Acked-by: Gregory Greenman <gregory.greenman@intel.com>

    I have tested this on top of Linux v5.17.3-rc1.

    Feel free to add my...

    Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # Linux v5.17.3-rc1 and
    Debian LLVM-14

    - Sedat -

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