On 1/21/25 1:40 AM, Hyesoo Yu wrote: > On Mon, Jan 20, 2025 at 03:36:08PM +0000, Matthew Wilcox wrote: >> On Mon, Jan 20, 2025 at 05:28:21PM +0900, Hyesoo Yu wrote: >>> If a slab object is corrupted or an error occurs in its internal >>> value, continuing after restoration may cause other side effects. >>> At this point, it is difficult to debug because the problem occurred >>> in the past. A flag has been added that can cause a panic when there >>> is a problem with the object. >>> >>> Signed-off-by: Hyesoo Yu <hyesoo.yu@xxxxxxxxxxx> >>> Change-Id: I4e7e5e0ec3421a7f6c84d591db052f79d3775493 >> >> Linux does not use Change IDs. Please omit these from future patches. >> >> Panicing is a very unfriendly approach. I think a better approach would >> be to freeze the slab where corruption is detected. That is, no future >> objects are allocated from that slab, and attempts to free objects from >> that slab become no-ops. I don't think that should be hard to implement. Freezing of slab is already done in some cases when corruption is detected - all objects are marked as used, and further freeing attempts on the slab are discarded. Perhaps not all cases, which could be improved. > Thanks you for your responce. That is my mistake. I will remove the change ID. > > I agree that freezing is better than recovery or panic for the system's stability. > However what I want from the patch is not just to make the system run stably. > I need to immediately trigger a panic to investigate the slub. IMHO it's a valid goal to panic more quickly when debugging, and enabling slub_debug means debugging is in progress (as opposed to normal production when we try to avoid panic). But making it possible to reuse the general panic_on_warn mechanism (which can be also expected to be enabled when debugging) is indeed preferable to introducing a new slab-specific flag. > I would like to analyze the corrupted data at that moment to check issues > like cache problem, user errors, system clock frequency and similar problems, > not just passing by without any issues. > > However I agree that panic is not a friendly approach. > I will modify it to notify the problem using warn() and then use > panic_on_warn to trigger panic. > > Thanks, > Regards. > >
